CHAPTER 1 Portrait of drinking water quality in small Quebec municipal utilities

Table des matières

Abstract. This study of small Quebec municipal drinking water utilities (i.e., those serving 10,000 or fewer people) focuses on a portrait of microbiological water quality (based on total and fecal coliform data) and distribution system management strategies. It also addresses relationships between some important water quality and operational parameters and management strategies on the one hand, and total or fecal coliform occurrences, on the other. Along with descriptive analyses, statistical means tests (Student t-tests) were performed to identify significant differences between utilities with high coliform occurrence and utilities with low coliform occurrence according to chlorine dose, distribution system flushings, pipe age, main breakage, and some environmental factors. Even though many interesting trends have been noted, only few of them resulted in statistically significant differences. For surface water utilities using chlorination alone, the mean difference of annual system flushings proved statistically significant. In addition, some agricultural land use indicators within the municipal territory appeared significantly correlated with coliform occurrences.

Key words: drinking water, water quality, small utilities, coliform occurrences, distribution system, Quebec

Résumé. Cette étude des petits systèmes municipaux de distribution d’eau potable du Québec (à savoir, ceux desservant 10 000 personnes ou moins) se focalise sur un portrait de la qualité microbiologique (basé sur des données de coliformes totaux et fécaux) et sur les stratégies de gestion des systèmes de distribution. L’étude s’intéresse également aux relations entre certains paramètres importants de qualité d’eau et les stratégies de gestion, de même que les épisodes de coliformes totaux ou fécaux. Parallèlement aux analyses descriptives, des tests statistiques de moyenne (tests du t de Student) ont été réalisés afin d’identifier les différences significatives entre les systèmes avec des épisodes fréquents de coliformes et les systèmes avec très peu de ces épisodes, et ce, en se basant sur les doses de chlore administrées, les rinçages du réseau de distribution, l’âge des conduites, les bris de conduites, et certains facteurs environnementaux. Bien que de nombreuses tendances intéressantes fussent notées, seulement quelques-unes donnèrent lieu à des différences statistiquement significatives. Pour les systèmes s’approvisionnant en eau de surface et pratiquant uniquement une chloration, la différence de moyenne portant sur le nombre annuel de rinçages s’est avérée statistiquement significative. En plus, certains indicateurs de la pression agricole sur le territoire des municipalités concernées apparurent significativement corrélés avec les épisodes de coliformes.

Mots-clés : eau potable, qualité de l’eau, petits systèmes, épisodes de coliformes, systèmes de distribution, Québec

In North America, small drinking water utilities (serving 10,000 or fewer people) have more difficulty than larger utilities to comply with the increasingly stringent regulations on distributed water quality. Indeed, small utilities have generally limited financial and technical resources allowing them to remove contaminants from raw water, to adequately operate the treatment and to implement management strategies to monitor and control water quality in the distribution systems (Gouvernement du Québec 1997; AWWA 2000). Among the important challenges for managers of small drinking water utilities are the necessity of simultaneously ensuring adequate microorganism inactivation in the plant and control in the distribution system and minimizing the formation of disinfection by-products potentially carcinogenic, such as trihalomethanes (THMs). When surface waters are utilized as raw water and chlorine is used as the principal disinfectant, such challenges become more considerable. In the U.S., small water utilities using either surface or groundwater will, in the coming months or years, have to comply with a number of new National Primary Drinking Water Regulations such as stage 1 of the Disinfectants/DBP rule (for residual disinfectant, maximum DBP levels and required treatment for organic carbon removal), the long term 1 Enhanced Surface Water Treatment Rule (requirements for CT calculations and filter monitoring/performance based on turbidity) and the Groundwater Rule (requirement of sanitary surveys, raw water monitoring and treatment based monitoring results)(USEPA 1998a; USEPA 1998b; USEPA 2000). In Canada, the federal government has elaborated guidelines for drinking water quality which are not mandatory, but that can be used by provinces to promulgate regulations for utilities within their territory (Santé Canada 1996). Before 2000, only two Canadian provinces, Alberta and Quebec (Gouvernement du Québec 1984), had promulgated mandatory regulations. Following the water contamination event in the small community of Walkerton (Ontario) during the summer of 2000, in which seven people died and more than 2,000 were taken ill, some other Canadian provinces (British Columbia, Nova Scotia, Ontario) published new regulations or updated their existing ones. This was the case of the Province of Quebec, where, in June 2001, the government published new Quebec Drinking Water Regulations (QDWR), whose application was mandatory for all utilities supplying water to more than 20 people (Gouvernement du Québec 2001). The 2001 QDWR constitutes a considerable update of the first regulations promulgated in 1984. Small utilities in Quebec, specially those using surface water, are particularly concerned by the 2001 QDWR, mainly because new requirements or stringent standards are considered for turbidity of clear water, microorganism inactivation (virus, Giardia and Cryptosporidium), bacterial monitoring, minimum levels of residual chlorine and maximum annual average THM levels in the distribution systems.

In the Province of Quebec, there are about 1,000 municipal utilities that serve between 51 and 10,000 people. According to the Quebec Ministry of Environment (QME), small utilities are known to have difficulties distributing water of good quality (Gouvernement du Québec 1997). Among Quebec small municipal utilities, about 350 supply chlorinated water with no previous physicochemical treatment to about 900,000 people (Gouvernement du Québec 1997). The relative high concentrations of natural organic matter (NOM) in most lakes, and the microbial pollution and high turbidity in southern Quebec streams, in particular associated with agricultural drainage, will make compliance with the 2001 QDWR apparently very difficult for most of these utilities. In accordance with the quality of the source water, particularly with the turbidity levels, most of these utilities will probably have to modify their water treatment strategy in the coming years.

Even if the 2001 QDWR are currently in application, and although small utilities will be all the more impacted by these regulations in terms of infrastructure and operation updating requirements, there is currently very little knowledge about the characteristics of these types of utilities, that is about their current state in terms of raw and distributed water quality, treatment and disinfection practices, infrastructure and the strategies to maintain the quality of water within the distribution system. In other words, at present there is no portrait of small utilities in Quebec allowing identification of their state and their problems. The aim of this paper is to establish a portrait of small drinking water utilities in Quebec using a combination of data developed by the authors and public data from diverse sources. Special emphasis will be placed on relating the state of the water quality (especially microbiological) with the existing management practices. This portrait will allow identification of their priorities and challenges for the upcoming years.

To establish a portrait of Quebec’s small utilities, three main sources of data were used. The first is a database managed by the QME, whose implementation is based on the routine reports carried out by water utilities to comply with 1984 QDWR (Database 1). Database 1 contains mainly information on microbiological water quality for small utilities. The second source of data was generated by the QME from sampling programs aiming to get information about, among other things, organic substances in the distribution system (Database 2). For the purpose of this research, Database 2 is comprised of THM data for small utilities. The third source of data is a database developed by the authors following a questionnaire-based survey directed to small utilities in Quebec (Database 3) in order to obtain information about utility characteristics (treatment, operations, management, maintenance, etc.). The fourth database comprised information on manure production in Quebec municipalities. Other published and unpublished data developed by others is also being considered in order to compare characteristics with those of other utilities.

According to the 1984 QDWR, drinking water utilities in Quebec have had to test their drinking water for specific parameters and send a report of results to the QME. The frequency for parameter monitoring depends principally on the utility size (that is, the population served). For small utilities, a very low monitoring frequency was required for most inorganic and organic water quality parameters (in general, one or two samples per year). These parameters include turbidity and residual chlorine, while total THMs were not required to be monitored even if a 350 µg/L maximum contaminant level existed. However, for microbiological quality control, from 1 to 10 samples per month (half of them taken at distribution system extremity) were required to be analyzed (for utilities serving 201 to 10,000 people) in order to comply with regulations concerning total and fecal coliforms, the only mandatory microbiological parameters according to 1984 QDWR (in June 2002, one year after the promulgation of the 2001, higher monitoring frequencies and additional microbiological parameters will be mandatory). According to this, data about total and fecal coliform tests currently constitute the only historical information on microbiological water quality based on utility compliance reports to QME. Consequently, database 1 consists of this kind of data for a three-year period, 1997, 1998 and 1999. By considering this period, it is possible to represent the recent trends and take into account variations from year to year. Database 1 includes information on 927 utilities. The latter are municipal utilities that serve from 201 to 10,000 people and which transmitted data on bacteriological control (i.e., fecal and total coliforms) to QME from 1997 to 1999. This choice was based on the fact that in accordance with the Quebec 1984 drinking water regulations (Gouvernement du Québec 1984), utilities serving from 51 to 200 people had to take only two samples per year for bacteriological analyses.

Since 1987, the QME has carried out sampling campaigns in selected Quebec water utilities in order to investigate, among other things, the occurrence of organic compounds (called the Surveillance Program ) (Riopel 1992). In this program, special attention has been focused on THM presence, particularly in vulnerable utilities, meaning those using surface waters with moderate or high organic carbon content, during the summer period (generally April to October). In general, within the Surveillance Program , samples for THMs were collected following chlorination and/or within the distribution system (about 1.5 km from the plant). Information generated from the Surveillance Program was used by the QME, for example, to evaluate the technical and economical feasibility of updating the 350 µg/L THM standard included in the 1984 QDWR (Vallée et al. 1993; Rousseau 1993; Tremblay et al. 1995). This THM standard was used only as a guideline for utilities, since monitoring requirements were not stipulated until the publication of the 2001 QDWR. Consequently, the information on THM occurrence provided by such sampling programs constitutes the only data available on a historical basis for Quebec water utilities. For the purpose of this research, Database 2 consequently consists of THM data from the small utilities, which took part at least once (all the year or only in summer) in the QME Surveillance Program during 1997, 1998 and 1999. These utilities had also to be among the 927 utilities of Database 1. As a result, 158 utilities were selected to form Database 2.

Databases 1 and 2 provide information about two key parameters characterizing water quality in distribution systems, coliform counts and THM. Because there is no database containing information on characteristics for small water utilities in Quebec, it was decided to conduct a questionnaire-based survey specifically for utilities serving from 201 to 10,000 people. Utilities selected for the survey were part of those included in Database 1. The survey completed in early 2000 was based on a questionnaire (see Appendix A) sent by mail to the principal manager/operator of each utility, asking for information about various issues. These issues include general characteristics (type of water source, population served, number of municipalities served, flowrates, etc.), water treatment procedures, disinfection issues, the quality of treated and distributed water, distribution system infrastructure and strategies to maintain water quality throughout the distribution system (see Appendix A). To validate the questionnaire (test), fifteen utilities were pre-selected at random and asked to respond. Some minor adjustments were made, based on their responses and comments. The questionnaire was then sent to about 25 percent of the 927 above-mentioned utilities (precisely, to 247 utilities). 114 small utilities returned the completed questionnaire, resulting in a response rate of about 46 percent. For specific questions within the questionnaire, however, the response rate varied considerably.

The portrait of small Quebec utilities was established based on all this information. The portrait comprises mainly the state of the microbiological water quality (Database 1), the state of the physicochemical water quality (Databases 2 and 3), an overview of management strategies which may influence water quality in the distribution system (Database 3), the relationships existing between microbiological quality and some management strategies (Databases 1 and 3), and the relationships between microbiological quality and agricultural (environmental) factors (Databases 1 and 4).

Most of the utilities where staff completed and returned the survey questionnaire operated very small utilities: 37 percent served from 201 to 1,000; 57 percent served from 1,001 to 5,000 and only 6 percent served from 5,001 to 10,000 people. Indeed, the survey response rate for utilities serving from 5,001 to 10,000 was found to be considerably lower than the response rate for the rest of the utilities (only 30.4 percent, while those serving from 201 to 1,000 and from 1,001 to 5,000 people had a response rate of 45.2 and 49.6 percent, respectively).

The majority of the surveyed utilities use surface water (i.e., water from lakes, rivers and streams, or groundwater directly influenced by surface water) (Table 1.1). The average served flowrate of distributed water was found to be about 2600 m3 per day according to 58 utilities who provided this information. Concerning the parameters of water quality, the response rate was relatively low (Table 1.2). This is understandable, considering that in 1984 QDWR, requirements for monitoring physicochemical parameters were weak. Thus, only data for parameters for which the response rate is above 15 percent are presented ( Figure 1.1). From the utilities providing quality parameter data, about 55 percent indicated the turbidity of their raw water to be lower than 1 NTU and about 28 percent to be higher than 5 UNT ( Figure 1.1-a). All groundwater utilities providing data (except two) have indicated turbidity levels lower than 1 UNT, whereas about one third of surface water utilities indicated average raw water turbidity higher than 5 UNT. It is important to mention that these turbidity values are average values, and that there may be large differences between the average and the maximum values encountered. These maximum turbidity values, which are not documented in this paper, are often the main source of problems. Only one third of utilities indicated the true colour to be lower than 15 TCU, whereas about the same proportion indicated true colour higher than 50 TCU ( Figure 1.1-b). Distribution

Figure 1.1. Distribution of water quality parameters among responding utilities: a, turbidity; b, colour; c, chlorine dose; and d, free chlorine residual. In brackets, number of utilities; lower bar, C10; upper bar, C90; cross, mean

of turbidity and colour values indicated by respondents was significantly higher in summer than in winter. A reasonable explanation for this is the presence of snow/ice layers in Southern Quebec surface watersheds during about four months of winter, which naturally protect sources of water from watershed runoff; another possible explanation is that because of high summer water temperatures, biological activity, planktonic in particular, is much higher.

Very few surveyed utilities indicated the use of a physicochemical treatment to remove turbidity, colour and organic carbon (Table 1.1). Practically all those utilities (with one exception) indicated the use of surface water as a water source. However, only 20 percent of utilities using surface water apply other treatment before chlorination (flocculation, settling, filtration). This is extremely different from the results obtained by others in the U.S., where 94 percent of surveyed small utilities indicated the use of at least filtration before disinfection (AWWA 2000), which is a direct consequence of the U.S National Primary Drinking Water Regulations (USEPA 1989). A more surprising result is that about one fourth of small Quebec utilities do not apply any treatment or disinfection (even for residual disinfectant maintenance) before delivering water into the distribution system. However, practically all of these utilities use groundwater as a raw water source (only one utility indicated using surface water without any treatment). All utilities that disinfect water before distribution use chlorine-based disinfectant, the same proportion with gas chlorine and with calcium/sodium hypochlorite. The use of hypochlorite as chlorine-based disinfectant appeared a little more widespread in small Quebec utilities (in 50 percent of utilities with disinfection) than in small U.S. utilities (34 percent) (AWWA 2000).

Applied chlorine doses before water distribution appeared to be higher in summer than in winter (Figure 1.1-c). This is not consistent with the fact that chlorine efficacy for micro-organism inactivation is higher in warm waters than in cold ones. However, these data appear realistic, considering that chlorine is the unique disinfectant applied in the surveyed utilities, that is, it is utilized simultaneously for ensuring inactivation and to maintain residual chlorine levels in the distribution system. For the latter purpose, higher chlorine doses are generally applied in summer to counterbalance the rapid decay of residual chlorine associated with higher water temperatures. These results are comparable to those of research programs undertaken by the authors with medium and large drinking water utilities of Quebec (Milot et al. 2000; Rodriguez et al. 2000; Rodriguez et al. 2001). It was also observed that average dose levels for small Quebec utilities were higher among utilities not using treatment (1.44 mg/L on average) than among those using treatment (1.12 mg/L on average). The higher doses were indicated by utilities that chlorinate surface waters without any previous physicochemical treatment (on average, 1.66 mg/L).

Concerning the physicochemical quality in treated water (before distribution), more than 80 percent of responding utilities indicated producing drinking water with less than 1 UNT and about 50 percent with less than 0.5 UNT, which is the standard of the Quebec 2001 QDWR (Figure 1.1-d). Moreover, all utilities reported having detectable levels for this parameter at the extremity of the distribution system: about 90 percent of the surveyed utilities reported levels for this parameter as being above 0.1 mg/L, whereas more than half reported values above 0.2 mg/L. These reported values appear higher than expected (especially in summer, when chlorine demand is high), considering that all utilities reported maximum residence time of water higher than 12 hours.

Considering the fact that a new standard for THMs is included in the Quebec 2001 QDWR (80 μg/L based on a quarterly annual average of samples taken at the extremity of the distribution system), it was considered appropriate to create a portrait of concentrations of this parameter in small Quebec utilities. Because only about 2 percent of responding utilities provided data about THMs, the portrait for these parameters was made on the basis of information included in Database 2 (Figure 1.2-a and Figure 1.2-b). According to results, in more than 30 percent of the utilities THM levels in the distribution system (that is, 1.5 km from the plant) were below 50 μg/L, and in more than 55 percent below 80 μg/L. Considering that all available data were generated from samples taken between April and October, it is probable that the annual average concentration of THMs for these utilities are in reality further below the THM values shown in Figure 1.2. This allows us to infer that, if for such utilities sample location represents the extremity of the distribution system, the majority of utilities would comply with the 2001 QDWR. According to Figure 1.2, utilities more susceptible to not complying with the THM standard are those that directly chlorinate surface waters (without any previous treatment). This is understandable, considering that THM precursors contained in raw waters (natural organic matter) are not removed by a physicochemical treatment in these utilities (mean TOC values are 3.22 mg/L, 3.81 mg/L, and 3.10 mg/L for groundwater plus chlorination alone, surface water plus chlorination alone and surface water plus treatment, respectively).

Figure 1.2. Average total THM concentrations according to: a, source water and treatment; b, utility size. In brackets, number of utilities; lower bar, C10; upper bar, C90; cross, mean. GW denotes Groundwater; SW denotes Surface Water.

To establish the portrait of microbiological water quality of the treated and the distributed water of small Quebec utilities, two indicators were built up using the information concerning total coliform (TC) and fecal coliform (FC) counts of database 1. To distinguish water samples considered microbiologically contaminated from those not contaminated, TC and FC data were initially converted in a dummy variable, indicating negative samples for TC (less than 10 organisms/100 mL, the maximum that does not systematically infringe upon the Quebec QDWR) and positive samples for TC (more than 10 organisms/100 mL). As for FC, any count different from zero was considered positive. From this new variable, two indicators were created. The first is called coliform episode and indicates one or a set of coliform positive samples occurring in a given distribution system during the three-year period (1997-1999), separated by at least 15 days from any other coliform positive sample in the same system. Such a criterion allows us to consider as a unique episode a number of positive samples occurring in a short period of time, and that have probably been associated with the same cause. This criterion also allows us not to consider as independent episodes the number of positive samples encountered following the intensive sampling program that generally follows the detection of a first positive sample for TC or FC (sampling carried out in the days following the laboratory results). The second indicator is called problematic utility and designates a utility that registered one or more coliform episodes in at least two of the three reference years. Consequently, utilities that registered no coliform episode, or had episodes in only one of the above-mentioned three years, were called nonproblematic utilities. This indicator allows distinguishing utilities with recurrent coliform occurrences from those with rare or no such occurrences.

Using data about total and fecal coliform of database 1 and the two indicators described above, a portrait of water quality was built up (Table 1.3.). Judging by data of Table 1.3., it would be hard to say that the respondents’ sample is representative of the population. However, since emphasis, as stated above, is put on relating the microbiological water quality with the existing management practices, the responding sample representativeness

* Population served

** Such abnormally high values are due to a very small total for this group (7 utilities only, compared to 83 among the 927).

may be of less concern, the central issue being rather to look for factors that may explain coliform appearances (i.e., episodes) in studied distribution systems. Moreover, even assuming that the survey sample (n = 247) is representative of the population of utilities (n = 927), it would be impossible to ensure that the respondents’ sample be representative, since one could have no control on the ultimate decision of a surveyed utility manager to respond or not. Information in Table 1.3. shows that even though the average percentage of coliform positive samples appears relatively low (about 1 percent), a high number of utilities have experienced microbiological water quality problems. According to the period under study, half of small Quebec utilities have experienced one or more coliform episodes. Among these utilities, the average number of episodes was about 2.4, whereas one fifth of utilities experienced more than three episodes (only 1 percent experienced all of them in one year). About 25 percent of all are problematic utilities, that is, having experienced recurrent microbiological problems in the distributed water. It is also observed that the portrait for microbiological water quality varies considerably according to the utility size. Indeed, more than 2 percent of all water samples collected in very small utilities (serving between 201 and 1,000 people) during the period under investigation were found coliform positive, this percentage being significantly higher during summer periods. However, no significant differences were observed between samples taken in the distribution system extremities in comparison with those taken in other locations (data not shown in Table 1.3.), which is a surprising result considering that it is well known that extremities constitute favourable locations for biofilm development and locations at which levels of residual chlorine are the lowest. Differences between utilities according to their size are also observable when examining both indicators, coliform episodes and problematic utilities, but such differences appeared less important (in terms of relative value) than in the case when only the percentage of coliform positive samples are examined. Such a result means that in very small utilities, a single coliform episode is represented by a higher number of positive TC or FC samples than in larger utilities. This suggests that in larger utilities (specially those serving between 5,000 and 10,000 persons), coliform episodes are relatively short, probably related to the shorter time required in these utilities (having generally more human and technical resources) for identifying the source of micro-organisms and the more rapid and efficient measures taken to resolve the problem.

Differences in microbiological water quality according to the utility size appear directly related to the source of water and the treatment process applied (Table 1.4.). Indeed,

* There was only one utility which used surface water and no treatment;  that case was ignored.

** So was the sole utility that used groundwater and treatment.

utilities using physicochemical treatment before chlorination, which are those that serve larger populations on average, have experienced significantly fewer problems of microbiological water quality in the distribution system than utilities using chlorination alone (from surface or groundwater sources) or utilities that do not use treatment at all. Utilities that encountered the most important and frequent difficulties of microbiological water quality in the distribution system are those that directly chlorinate surface waters. One can notice from the analysis made earlier that the same group of utilities (which represent one third of small Quebec utilities) are those that also have the highest values of THMs. Finally, this group is also the one that encompasses the highest percentage of utilities that experienced at least one coliform episode, the highest percentage of problematic utilities, and the highest average number of episodes. Generally speaking, the coliform occurrences appear more recurrent for utilities supplied by surface sources, confirming the high vulnerability to microbial intrusion for such utilities.

Small utilities were also asked during the survey for information about characteristics of their infrastructure and the routine and long-term strategies to manage water quality in the distribution system. Issues investigated, such as rechlorination and pipe characteristics and maintenance (age, material, break rate, corrosion strategies and pipe cleaning strategies), can directly or indirectly affect the water quality within the distribution system. Table 1.5. presents the information obtained for some of these issues.

Residual chlorine is recognized to be an indicator of water quality in a distribution system, particularly because it can reduce the risk of microbial regrowth (Sobsey et al. 1993; Sérodes et al. 1998; Haas 1999; LeChevallier 1999). It is noteworthy however that the issue of maintaining a residual is not clear cut, and has generated some controversy in recent years. In this respect, a number of authors consider that the necessity of chlorine residual maintenance is arguable due to its poor efficacy to inactivate waterborne pathogens in drinking water distribution systems (Payment 1999; van der Kooij et al. 1999). Because chlorine reacts with organic and inorganic compounds when added to water in the plant before distribution, residual chlorine levels can rapidly decay and even disappear at extremities, especially for utilities with extensive distribution systems and long retention times (Kirmeyer et al. 1993; Reiber 1993). Rechlorination of water within the distribution system may counterbalance initial chlorine decay. According to small Quebec utility respondents, only a small percentage of utilities (about 10 percent), particularly the larger ones (in terms of both population served and pipeline length), use rechlorination facilities within the distribution system to maintain sufficient residual chlorine levels. However, it was found that the average residual chlorine for small responding utilities using rechlorination is practically the same in winter and significantly lower in summer than average residual for utilities not practicing rechlorination. It is interesting to observe that almost all responding utilities that rechlorinate are surface water utilities that do not use any treatment before chlorination. This is probably due to the fact that the chlorine demand following the dose application is higher for those utilities because of the lower quality of water. Thus, to compensate for high initial chlorine demand, rechlorination generally appears to be a good strategy to ensure minimal levels of residual chlorine and minimize the probability for bacterial regrowth.

The issue of water main assessment and associated research needs is well documented (AWWA 1994; Rajani et al. 1995; Kitaura et al. 1996; Makar 2000; Rajani et al. 2000). Aging distribution system pipes, in particular those made of iron-based material, can cause water quality deterioration within the distribution system, especially through corrosion. In addition to favouring precipitation of metal ions, which can cause coloured water, pipe corrosion may favour the formation of tubercles within which a biological film can form or cause breaks in the main, both aspects being favourable conditions for deterioration of microbiological water quality (LeChevallier et al. 1990). Distribution system pipes of the responding small utilities appeared, surprisingly, relatively older in comparison to medium and large utilities in Quebec. Indeed, an average of about 57 percent of pipes of small Quebec utilities are, according to respondents, 35 years old or less, compared to an average of 65 percent of medium and large Quebec utilities (Villeneuve et al. 1998; Fougères et al. 1998), and 24 percent of responding utility pipes are 20 years or less, compared to 34 percent for medium and large utilities. However, only a minority (about 30 percent) of responding small Quebec utilities acknowledged that their pipes suffered from corrosion problems, and only a third of those utilities implemented corrosion control strategies (generally by ensuring a relatively high pH by adding calcium or phosphate). This result appeared surprising, considering that on average, 63 percent of the distribution system pipes are made of cast iron (on average, 28 percent made of PVC).

Concerning the infrastructure of the distribution system, small Quebec utilities reported an average rate of breaks which can be considered acceptable according to McDonald et al. 1997, who judged that a main break rate can be considered abnormally high when it exceeds 40/100km/year (78 percent have had this many or less). However, it is observed that only half the utilities reported a break rate that is lower than 25/100km/year, which is the average for distribution systems of Ontario towns, according to the Ontario Sewer and Watermain Contractors Association (CMCH 1992). The average break rate indicated by responding utilities (about 29/100km/year) is also more than double the one for US towns distribution systems, that is, about 13/100km/year (AWWA 1994). Results indicate that the average main break rate for responding utilities more than 50 years old (30/100km/year) is slightly lower than the one for those with ages ranging from 31 through 50 years (32/100km/year), whereas, as expected, the younger utilities (30 years old or less) experienced much fewer main breaks (27/100km/year). The average for all utilities more than 30 years old is also about 32/100km/year. Surprisingly, the average main break rate for utilities which suffer from corrosion problems is slightly lower than the one for those not experiencing such problems: 29/100km/year and 30/100km/year, respectively. Moreover, the mean age for utilities experiencing corrosion (about 41 years) is higher than the one for utilities without corrosion (about 35 years). Utilities applying corrosion control strategies had significantly fewer breaks (24/100km/year) than those, which have not developed such strategies (33/100km/year), but the former are younger than the latter (mean ages of 39 and 44 years, respectively). So, it seems that all of this is tied to pipe age, hence the importance of an adequate pipe replacement policy. Besides, according to Villeneuve et al. 1998, only about one percent of the total pipe mileage of Quebec utilities is replaced every year. This replacement rate may appear too low, judging by the above-mentioned (observed) breakage rates.

One important strategy for maintenance of water quality in distribution systems is to carry out periodic flushing in order to take out different natures of deposits in the pipe wall internal surface. Flushing is considered an efficient strategy; particularly to take out biofilm and corrosion tubercles which both favour microbiological deterioration within the distribution system (Antoun et al. 1999; Duranceau et al. 1999). All small Quebec utilities reported flushing the distribution system at least once each year and more than half reported at least 2 flushings. Most of the utilities carrying out only one flushing usually made it later in summer or in fall. According to Antoun et al. 1999, this may be a good management strategy, because it ensures pipeline cleaning after the period within which biofilm development is most proliferate. This similarity appears surprising, but encouraging, considering that generally speaking, larger utilities possess higher financial capacities for maintenance of infrastructure. However, it was also observed that very small Quebec water utilities (those serving less than 1,000 persons) carry out as many flushings as larger ones (on average 2 per year).

The portrait of microbiological water quality was also investigated in accordance with the management strategies mentioned earlier. It was developed principally by combining the information contained in Databases 1 and 3. Table 1.6. to Table 1.9. present the results concerning these analyses. Particular attention was paid to the more vulnerable utilities, meaning those which directly chlorinate surface waters. According to results, utilities not having water quality problems generally apply lower chlorine doses, during both winter and summer (Table 1.6.). These results appear surprising, because it is expected that higher chlorine doses ensure higher microbial inactivation and higher free chlorine residual concentration and, thus, greater protection from microbiological degradation of water quality in the distribution system. These results suggest that in small utilities where there exist recurrent microbiological problems, managers use higher chlorine doses as a corrective measure, but that such strategy does not necessarily prevent or reduce these problems. Certainly, increasing the applied chlorine dose does not necessarily ensure an increase of residual chlorine in every location of the distribution system, and thus does not necessarily ensure an improvement of microbiological water quality, since many other factors can be related to coliform regrowth in drinking water (LeChevallier 1996).

According to Table 1.7., utilities with recurrent water quality problems practice less flushings on average of their distribution system than those which do not have such problems. Even if the median for the number of annual flushings is similar for utilities with and without recurrent problems, it appears that utilities which make two or more flushings per year have better results within a perspective of microbiological water quality than those which make only one. This trend was much stronger and statistically significant (P < 0.1) for utilities which directly chlorinate surface waters. The results in Table 1.7. suggest that generally, flushing has real positive impacts on distribution system water quality.

As mentioned earlier, it is well known that aging distribution systems may favour corrosion and biofilm development in the pipe wall, thereby possibly affecting water quality. However, according to Table 1.8., no significant differences in microbiological water quality were observed in small Quebec utilities according to the age of the distribution system, even if the age variations of the utilities under study are important (as presented earlier in Table 1.5.). A possible explanation for this is that the average age of the distribution system pipes is not necessarily representative of the entire utility (that is, very large age pipe variations can exist in a single utility), because it is very probable that some

P : significance level of the means test

P : significance level of the means test

P : significance level of the means test

P : significance level of the means test

pipes have never been replaced, while others could have been replaced very recently. However, no information about pipe replacement rate was available from Database 3.

Finally, even if pipe breaks are known to be a possible source of microbial intrusion in distribution systems, no significant differences of the annual breakage rate were observed between utilities having water quality problems and those not having them (Table 1.9.). However, a surprising result is observed for utilities that directly chlorinate surface waters. Among these utilities, those not having microbiological problems at all (that is any episode at all) have significantly higher pipe breakage rates (for both mean and median values) than those that do have quality problems. In addition, the average pipe breakage rate in these utilities appeared higher than the maximum acceptable recommended (Ontario, MacDonald 1994). Many possible explanations may be put forward to explain this apparently illogical result. First, it appears that extreme breakage statistics are more frequent among utilities experiencing 29 breaks/100km/year (the overall average value) or fewer. Second, the relative weight of utilities practicing chlorination alone (which were found to be more often problematic than all others) is bigger among this same group. Third, the age, type and corrodibility of pipe material may also be involved; for instance, for utilities having less than 50 percent of their pipelines made of PVC, the average number of main breaks is much higher than that for utilities with more than 50 percent PVC (32 breaks/100km/year and 22 breaks/100km/year, respectively).

As part of Quebec’s recent regulations about agricultural pollution, and in order to control cattle breeding expansion in locations where agriculture is already too intensive, all municipalities of the province have been designated a manure status (as specified in data received from QME). Such a status is a function of the intensity of agriculture pressure on their territory (soils). This factor is measured by the annual balance of phosphorus in terms of kilograms of phosphorous (P2O5) per hectare. It considers total manure production within the municipality, the nutrient requirements of crops and the cultivated area. When the annual balance is more than 20 kg P2O5/ha/year, the authorities consider the corresponding municipality as being in manure surplus. However, for a number of municipalities, even a zero annual balance is considered an administrative surplus, because they are situated in watersheds with already significant phosphorus excess. Even if such an annual balance was not calculated based on watershed limits but rather on municipal limits, it can be used as an indicator of the susceptibility of surface waters to be contaminated by surface or subsurface runoff. For the purpose of this study, information about the manure status had been considered under four variables in order to associate it with water quality in small utilities. These variables are: zone with/without manure production, zone administratively/not administratively in a surplus situation, annual manure balance less or equal to/more than 0 kg P2O5/ha, and surplus of phosphorus less/equal to or more than 20 kg P2O5/ha/year. The impact of each of these factors on microbiological water quality is analyzed in Table 1.10. The results indicate that on the whole, utilities located in zones with high agricultural pressure experienced more water quality problems (related to total or fecal coliforms). The impact of agricultural pressure on water quality appeared significant for the more vulnerable utilities, that is, those chlorinating surface water without any previous treatment. Indeed, two of the four manure-related variables, (i.e., “administratively in phosphorus surplus” and “phosphorus annual balance”) were found to be significantly correlated with the variable “number of coliform episodes”. This suggests that future controlling of cattle breeding expansion will have a considerable effect on small vulnerable utilities.

In order to evaluate interactions between variables or potential collective impacts of the studied management strategies on microbiological water quality, multivariate analyses were carried out. Three variables: “problematic/nonproblematic”, “episodes/no episode”, and “number of episodes” had to be explained. Because the first two are dichotomous, a binary stepwise logistic regression analysis was performed to search for factors explaining them.

P : significance level of the means test

For the continuous variable (“number of episodes”), a linear regression analysis was used. First, analyses were carried out for all responding utilities, and then for respondents using surface water and chlorination alone. When all respondents are considered, the only variable that exhibits a significant relationship with the three specified dependent variables is the treatment type. This is obvious, and needs no particular explanation. So, no multivariate model emerges for the whole set of respondents. As for surface water utilities using chlorination alone, one model comes out and indicates that 33 percent of the explained variance related to the dichotomous variable “problematic/nonproblematic” is tied to variables “phosphorus annual balance” and “phosphorus surplus more than 20 kg P2O5/ha/year”, with the model being significant at the 1 percent (0.01) level (logistic regression analysis: χ2 = 11.9; R2 = 0.33; P = 0.003). This suggests that the fact that a surface water utility with chlorination alone is either problematic or nonproblematic with regard to microbiological quality (total or fecal coliforms) is relatively easy to explain by the agricultural land use of the municipality where the utility is located. Such an indication seems easily explicable, since it is well known that cattle feces and piggery effluents contain great quantities of bacteria and parasites that may eventually find their way into water springs by means of agricultural runoff or infiltration into ground water.

This research has documented some important characteristics of small Quebec drinking water utilities. First of all, one notes that even though all of these utilities are called small utilities , and are supposed to have very comparable financial and technical resources, the quality of their distributed water may vary considerably. Actually, three groups of utilities emerged during this study: first, utilities which never experienced problems with microbiological water quality during the reference three-year period (1997 through 1999); second, utilities that occasionally encountered difficulties complying with drinking water regulations relating to total coliforms; and, third, utilities which very often infringed upon quality standards. The first two groups can be considered as distributing relatively safe water to their customers. The last group obviously consists of utilities that have major problems.

Most of the latter are utilities that directly chlorinate surface waters without any other treatment. These problematic utilities may need to acquire a treatment facility, especially considering the new and much more stringent QDWR promulgated by the Quebec government in June 2001. These utilities, unable to comply with coliform standards, will now have to cope with parasites, viruses, and monitoring of trihalomethanes, to name but a few. It is hard to believe that small problematic utilities will overcome such obstacles, without managing, at least in a filtration facility, to reduce NOM content in their distributed water. In any case, they will have to apply filtration in a relatively near future, since new QDWR (that will come into force in June 2002, except for a few recently amended clauses including filtration, the effective date for the latter being postponed until June 2005 for utilities serving fewer than 50,000 people, and until June 2007 for those serving 50,000 or more people) make filtration practically inevitable for all Quebec surface water utilities.

Concerning infrastructure and water quality maintenance, small utilities appeared to be aging, compared to medium-size and large ones. This may be attributable to the fact that most of medium-size and large utilities pertain to numerous relatively young suburbs that grew all around big Quebec metropolitan areas like Montreal or Quebec City, some 40 to 50 years ago. Among distribution water quality management strategies analyzed, some interesting trends were noted when comparing mean values for utilities with no episode to those with episodes on the one hand, and for problematic and nonproblematic utilities, on the other. However, very few of these trends were confirmed by results of bivariate or multivariate analyses (possibly due to the very discrete nature of microbial dissemination in distribution systems). Apart from treatment-related variables, only the manure-related variables exhibit some statistical impact. This may not be surprising, considering that many of the responding utilities are located in zones under high agricultural pressure.

In terms of strict public health concern, it must be underlined that the so-called problematic utilities are not necessarily serving water bearing more of a health threat than the water served by the nonproblematic ones. In fact, most of reported episodes concern total coliforms, which may tell more about the general salubriousness of the distribution system than about real health hazards. Moreover, databases used for this study did not include data on parasites like Giardia lamblia and Cryptosporidium parvum , nor on viruses or other waterborne pathogens. These micro-organisms are of great concern, since they have been tied to waterborne disease outbreaks in the United States and elsewhere. The only reason these parameters were not included in this study is that there is an almost total lack of data about them in small Quebec utilities.

The fact that data came from different sources has led to different data considerations, which, to some extent, hindered this study. This situation may render difficult a comparison of these results to those of other studies. Despite these limitations, this study has the advantage of trying to create an overall portrait of microbiological and physicochemical water quality in small Quebec utilities, and trying to establish and explain relationships between the portrayed quality and some management practices or environmental factors (manure). This may be interesting for those who want to know more about the specificity of small utilities and the challenges they face, for instance, from a regulatory point of view.

Finally, it is worth mentioning that historical atypical bacteria data and water boiling notices data were obtained from some of the studied herein small utilities. These data strongly support the distinction made between nonproblematic and problematic utilities (see Appendix B). However, the data were found about two years after the management practices survey answers were obtained. At that time, this part of the research was already completed. That is why atypical bacteria and water boiling notices data were not included in this chapter.

Antoun, E.N., Dyksen, J.E., and Hiltebrand, D.J. 1999. Unidirectional flushing – a powerful tool. J. Am. Water Works Assoc. 91: 62-71.

AWWA. 1994. An assessment of water distribution systems and associated research needs. American Water Works Association, Denver, CO.

AWWA. 1998. Water:\stats : the water utility database. American Water Works Association, Denver, CO.

AWWA. 2000. Disinfection at small systems. AWWA Water Quality Division Disinfection Systems Committee report. J. Am. Water Works Assoc. 92: 24–31.

CMCH. 1992. Urban infrastructure in Canada. Canada Mortgage and Housing Corporation, Ottawa.

Duranceau, S.J., Poole, J., and Foster, J.V. 1999. Wet-pipe fire sprinklers and water quality. J. Am. Water Works Assoc. 91: 78-90.

Fougères, D., Gaudreau, M., Hamel, P.J., Poitras, C., Sénécal, G., Trépanier, M., Vachon, N., et Veillette R. 1998. Évaluation des besoins des municipalités québécoises en réfection et construction d’infrastructures d’eaux. INRS-Urbanisation, Montréal, 266 p.

Gouvernement du Québec. 1984. Règlement sur l’eau potable. Éditeur officiel du Québec, Québec. 7 p.

Gouvernement du Québec. 1997. L’eau potable au Québec. Un second bilan de sa qualité : 1989–1994. Ministère de l’Environnement et de la Faune, Québec. 36 p.

Gouvernement du Québec. 2001. Règlement sur la qualité de l’eau potable. Ministère de l’Environnement, Québec. 19 p.

Haas, C.N. 1999. Benefits of employing a disinfection residual . Journal of Water Supply : Research and Technology – Aqua 48: 11–15.

LeChevallier, M.W., Schulz, W.H., and Lee, R.G. 1990. Bacterial nutrients in drinking water. In : Assessing and controlling bacterial regrowth in distribution systems. AWWARF (ed.), pp. 143–201. American Water Works Association Research Foundation, Denver, CO.

LeChevallier, M.W., Welch, N.J., and Smith, D.B. 1996. Full-scale studies of factors related to coliform regrowth in drinking water. Appl. Environ. Microbiol. 62: 2201–2211.

LeChevallier, M.W. 1999. The case for maintaining a disinfectant residual. J. Am. Water Works Assoc. 91: 86–94.

Levallois, P. 1997. Qualité de l’eau potable et trihalométhanes . Bulletin d’Information en Santé Environnementale (BISE) 8: 1–4.

Kirmeyer, G.J., Foust, G.W., Pierson, G.L., Simmler, J.J., and LeChevallier, M.W. 1993. Optimizing chloramine treatment. AWWARF and AWWA, Denver, CO.

Kitaura, M., and Miyajima, M. 1996. Damage to water supply pipelines. Soils and Foundations 36: 325-333.

Makar, J.M. 2000. A preliminary analysis of failures in grey cast iron water pipes. Institute for Research in Construction, National Research Council Canada, 17 p.

McDonald, S., Daigle, L., and Félio, G. 1997. Water distribution and sewage collection in Canada – assessing the condition of municipal infrastructure, results from questionnaires to Canadian municipalities. Client Report A-7016.1, Institute for Research in Construction, National Research Council Canada.

Milot, J., Rodriguez, M.J., and Sérodes, J. 2000. Modeling the susceptibility of drinking water utilities to form high concentrations of trihalomethanes.  Journal of Environmental Management 60: 155–171.

Payment, P. 1999. Poor efficacy of residual chlorine disinfectant in drinking water to inactivate waterborne pathogens in distribution systems. Canadian Journal of Microbiology 45: 709–715.

Rajani, B., and McDonald, S. 1995. Water main break data for different pipe materials for 1992 and 1993. Report No. A-7019.1, National Research Council, Ottawa, Canada.

Rajani, B.B., Makar, J.M., McDonald, S.E., Zhan, C., Kuraoka, S., Jen, C.-K., and Viens, M. 2000. Investigation of grey cast iron water mains to develop a methodology for estimating service life. AWWARF and AWWA, Denver, CO, 266 p.

Reiber, S. 1993. Chloramine effects on distribution system materials. AWWARF and AWWA, Denver, CO.

Riopel, A. 1992. Les trihalométhanes dans les petits systèmes de distribution au Québec: campagnes d’échantillonnage de 1987 et 1988. Direction des écosystèmes urbains, Ministère de l’Environnement, Gouvernement du Québec, 21 p.

Rodriguez, M.J., Sérodes, J.-B., and Morin, M. 2000. Estimation of water utility compliance with trihalomethane regulations using a modelling approach . Journal of Water Supply : Research and Technology – Aqua 49: 57–73.

Rodriguez, M.J., and Sérodes, J.-B. 2001. Spatial and temporal evolution of trihalomethanes in three water distribution systems. Water Res. 35: 1572–1586.

Rousseau, H. 1993. Suivi des concentrations de THM dans huit (8) réseaux de distribution d’eau potable au Québec. Division des eaux de consommation, Direction des écosystèmes urbains, Ministère de l’Environnement et de la Faune, Gouvernement du Québec, 54 p.

Santé Canada. 1996. Recommandations pour la qualité de l’eau potable au Canada. Sixième édition. Édition du Groupe Communication Canada, Ottawa, 102 p.

Sérodes J.B., Rodriguez, M.J., and Ponton, A. 1998. Development and on-site evaluation of a decision-making tool for chlorine disinfection dose and residual control. Presented at the 8th National Conference on Drinking Water, Canadian Water and Wastewater Association (CWWA), Quebec City, Quebec, Canada. 28-30 October.

Sobsey, M.D., Dufour, P.A., Gerba, C.P., LeChevallier, M.W., and Payment, P. 1993. Using a conceptual framework for assessing risks to health from microbes in drinking water. J. Am. Water Works Assoc. 85: 44–48.

Tremblay, H., et Trinh-Viet, H. 1995. Réseaux municipaux visés par le règlement sur l’eau potable susceptibles de présenter une concentration moyenne annuelle de THM supérieure à 100 μg/l : estimation des coûts de réalisation des ouvrages. Service de l’assainissement des eaux et du traitement des eaux de consommation, Ministère de l’Environnement et de la Faune, Gouvernement du Québec, 31 p.

USEPA. 1989. National Primary Drinking Water Regulations : filtration, disinfection, turbidity, Giardia lamblia, viruses, Legionella, and heterotrophic bacteria. Final rule. Fed. Reg., 54:124:27486.

USEPA. 1998a. National Primary Drinking Water Regulations : disinfectants and disinfection by-products. Final rule. Fed. Reg., 63:241:69389.

USEPA. 1998b . National Primary Drinking Water Regulations : interim enhanced surface water treatment rule. Fed. Reg., 63:241:69477.

USEPA. 1999. Handbook for capacity development: developing water system capacity under the Safe Drinking Water Act as amended in 1996. United States Environmental Protection Agency, Office of Water (4606), EPA 816-R-99-012.

USEPA. 2000. National Primary Drinking Water Regulations : groundwater rule. Proposed rule. Fed. Reg., 65:91:30194.

van der Kooij, D., van Lieverloo, J.H.M., Schellart, J., and Hiemstra, P. 1999. Maintaining quality without a disinfectant residual. J. Am. Water Works Assoc. 91: 55–64.

Villeneuve, J.P., and Hamel, P.J. 1998. Synthèse des rapports INRS-Urbanisation et INRS-Eau sur les besoins des municipalités québécoises en réfection et construction d’infrastructures d’eaux. INRS-Urbanisation, Montréal, 50 p.