| #Q001 | monitoring | health | recommended | E. coli multi-barrier monitoring | drinking water | E. coli monitoring should be used, in conjunction with other indicators, as part of a multi-barrier approach to producing drinking water of an acceptable quality. | When producing drinking water | high |
| #Q002 | operational | health | recommended | Unsafe water declaration regardless of analysis | drinking water | Therefore, if a vulnerability assessment or inspection of a drinking water system shows that an untreated supply or treated water (e.g., during distribution and storage) is subject to fecal contamination, or that treatment is inadequate, the water should be considered unsafe, irrespective of the results of E. coli analysis. | If vulnerability assessment or inspection shows subject to fecal contamination or inadequate treatment | high |
| #Q003 | operational | treatment | recommended | Disinfectant residual maintenance | drinking water | In systems with a distribution system, a disinfectant residual should be maintained throughout the system at all times. | Systems with a distribution system | high |
| #Q004 | monitoring | operational | recommended | Treatment plant effluent monitoring | drinking water | E. coli should be monitored at least weekly in water leaving a treatment plant. | Municipal-scale systems | high |
| #Q005 | monitoring | operational | recommended | Combined operational indicator monitoring | drinking water | E. coli tests should be used in conjunction with other operational indicators, such as residual disinfectant and turbidity monitoring as part of a source-to-tap or water safety plan approach. | Municipal-scale systems | high |
| #Q006 | monitoring | health | recommended | Distribution system population-based sampling | drinking water | In municipal-scale distribution and storage systems, the number of samples collected for E. coli testing should reflect the size of the population being served, with a minimum of four samples per month. | Municipal-scale distribution and storage systems | high |
| #Q007 | monitoring | operational | recommended | Distribution system operational indicators | drinking water | Operational indicators (e.g., disinfectant residual, pressure monitoring) should be used in conjunction with E. coli tests as part of a source-to-tap or water safety plan approach. | Municipal-scale distribution and storage systems | high |
| #Q008 | reporting | health | recommended | Immediate notification of E. coli detection | drinking water | If E. coli is detected in a sample of drinking water from a municipal-scale drinking water system (i.e. water leaving a treatment plant, or in a distribution or storage system), the system owner/operator and the laboratory processing the samples should immediately notify the responsible authorities. | Detection of E. coli in municipal-scale drinking water system | high |
| #Q009 | corrective_action | operational | recommended | Immediate follow-up actions for E. coli detection | drinking water | The system owner/operator should also: immediately resample and test the E. coli -positive site(s) and adjacent sites; conduct an assessment to ensure treatment barriers are operating correctly (this may include gathering information on water treatment performance and other operational monitoring data); and carry out any corrective actions necessary (See Section 3.1.4) in order to resume control or normal system operations. | Detection of E. coli in municipal-scale drinking water system | high |
| #Q010 | reporting | health | recommended | Boil water advisory issuance | drinking water | If resampling and testing confirm the presence of E. coli in drinking water, the system owner/operator should immediately issue a boil water advisory in consultation with the responsible authorities, and carry out the appropriate corrective actions (Section 3.1.4). | If resampling and testing confirm the presence of E. coli | high |
| #Q011 | administrative | health | recommended | Surveillance cooperation | drinking water | The owner/operator should also cooperate with the responsible authorities in any surveillance for possible waterborne disease outbreaks. | During confirmed E. coli contamination event | high |
| #Q012 | corrective_action | health | recommended | Immediate boil water advisory triggers | drinking water | A boil water advisory should be immediately issued where there is evidence of: a significant failure of a critical treatment barrier; or illness in the community that is suspected to be associated with drinking water. | Failure of critical treatment barrier or suspected community illness | high |
| #Q013 | corrective_action | operational | recommended | Execution of corrective actions | drinking water | If resampling and testing confirms the presence of E. coli in drinking water, the owner/operator of the waterworks system should carry out appropriate corrective actions, which could include the following measures: Verify the integrity and the optimal operation of the treatment process. Verify the integrity of the distribution system. Verify that the required disinfectant residual is present throughout the distribution system. Increase disinfectant dosage, flush water mains, clean treated-water storage tanks (municipal reservoirs and domestic cisterns), and check for the presence of cross-connections and pressure losses. The responsible authority should be consulted regarding the correct procedure for dechlorinating water being discharged into the environment. Sample and test the E. coli -positive site(s) and locations adjacent to the E. coli -positive site(s)... Conduct an investigation to identify the problem and prevent its recurrence... Continue selected sampling and testing... of all identified sites during the investigative phase | Confirmed presence of E. coli via resampling | high |
| #Q014 | administrative | reporting | guidance | Rescinding boil water advisory procedure | drinking water | Once the appropriate corrective actions have been taken and only after a minimum of two consecutive sets of bacteriological samples, collected 24 hours apart, produce negative results, an E. coli -related boil water advisory may be rescinded. | Following corrective actions and two consecutive negative samples 24 hours apart | high |
| #Q015 | monitoring | health | recommended | Private well testing frequency | drinking water | Homeowners with private wells should regularly test (at a minimum two times per year) their well for E. coli , ideally during these same at-risk times. | Private wells | high |
| #Q016 | monitoring | health | recommended | Testing of new or rehabilitated wells | drinking water | New or rehabilitated wells should also be tested before their first use to confirm microbiological safety. | Before first use of new or rehabilitated wells | high |
| #Q017 | administrative | operational | recommended | Compliance with jurisdictional requirements for residential-scale systems | drinking water | Residential-scale systems that serve the public may be subject to regulatory or legislative requirements and should follow any actions specified by the responsible drinking water authority. | Residential-scale systems that serve the public | high |
| #Q018 | reporting | health | recommended | Notification of E. coli in residential-scale public systems | drinking water | If E. coli is detected in a sample of drinking water from a residential-scale system that serves the public, the system owner/operator and the laboratory processing the samples should immediately notify the responsible authorities. | E. coli detection in residential-scale system that serves the public | high |
| #Q019 | monitoring | health | recommended | Resampling of residential-scale public systems | drinking water | The system owner/operator should also immediately resample and test the drinking water to confirm the presence of E. coli. | Following positive E. coli result in a residential-scale system serving the public | high |
| #Q020 | corrective_action | health | recommended | Homeowner advisory for private supplies | drinking water | If E. coli is detected in a private drinking water supply, homeowners should also be advised to boil their drinking water or to use an alternative supply that is known to be safe; and to resample and test their drinking water to confirm the presence of E. coli. | E. coli detection in private drinking water supply | high |
| #Q021 | corrective_action | health | recommended | Immediate corrective actions for contaminated sources | drinking water | If resampling confirms that the source is contaminated with E. coli , the system owner/operator should immediately carry out the appropriate corrective actions (see Section 3.2.3 and 3.2.4). | Resampling confirms source is contaminated with E. coli | high |
| #Q022 | corrective_action | operational | recommended | Physical system evaluation for disinfected supplies | drinking water | The first step, if it has not already been taken, is to evaluate the physical condition of the drinking water system as applicable, including water intake, well, well head, pump, treatment system (including chemical feed equipment, if present), plumbing, barriers to animal access (e.g., birds, vermin), and the surrounding area. Any identified faults should be corrected. | During corrective actions for disinfected supplies | high |
| #Q023 | monitoring | operational | recommended | Post-correction testing for disinfected supplies | drinking water | After the necessary corrective actions have been taken, samples should be collected and tested for E. coli to confirm that the problem has been corrected. | Following corrective actions in disinfected supplies | high |
| #Q024 | corrective_action | operational | recommended | Corrective actions for undisinfected wells | drinking water | The first step, if it has not already been taken, is to evaluate the condition of the well, well head, pump, plumbing, and surrounding area. Any identified faults should be corrected. If the physical conditions are acceptable, then the following corrective actions should be carried out: Shock-chlorinate the well and plumbing system. Flush the system thoroughly and retest to confirm the absence of E. coli. | During corrective actions for undisinfected wells | high |
| #Q025 | monitoring | operational | recommended | Delay of confirmatory testing post-shock-chlorination | drinking water | Confirmatory tests should be delayed until either 48 hours after tests indicate the absence of a chlorine residual or five days have elapsed since the well was treated. | Following shock-chlorination of undisinfected wells | high |
| #Q026 | administrative | reporting | recommended | Rescinding boil water advisory for residential-scale systems | drinking water | Once the appropriate corrective actions have been taken, an E. coli -related boil water advisory should be rescinded only after a minimum of two consecutive sets of samples, collected 24 hours apart, produce negative results. | Rescinding boil water advisory | high |
| #Q027 | monitoring | health | recommended | Long-term follow-up testing | drinking water | Additional tests should be taken after three to four months to ensure that the contamination has not recurred. | Following resolution of a contamination event in residential-scale systems | high |
| #Q028 | administrative | operational | recommended | Direction of analyses | drinking water | All analyses for E. coli should be carried out as directed by the responsible drinking water authority. | | high |
| #Q029 | administrative | operational | recommended | Quality assurance program requirement | drinking water | To ensure reliable results, a quality assurance program, which incorporates quality control practices, should be in place. | Analytical testing facilities | high |
| #Q030 | operational | operational | recommended | Use of test kits | drinking water | Analyses conducted using test kits used should be performed according to the manufacturer's instructions. | When using test kits for analysis | high |
| #Q031 | monitoring | operational | mandatory | Proper sampling procedures | drinking water | Proper procedures for collecting samples must be observed to ensure that the samples are representative of the water being examined. | | high |
| #Q032 | monitoring | operational | recommended | Sample packing | drinking water | Generally, samples for microbiological testing should be packed with ice packs but protected from direct contact with them to prevent freezing. | During sample packing | high |
| #Q033 | monitoring | operational | recommended | Sample transport temperature | drinking water | During transport, samples should be kept cool but unfrozen at temperatures between 4 and 10°C | During sample transport | high |
| #Q034 | monitoring | operational | recommended | Timely analysis of E. coli samples | drinking water | To avoid unpredictable changes in the bacterial numbers of the sample, E. coli samples should always be analyzed as soon as possible after collection. | Following sample collection | high |
| #Q035 | administrative | operational | recommended | Sample labeling | drinking water | Samples should be labelled according to the requirements specified by the responsible drinking water authority and the analytical laboratory. | Sample documentation | high |
| #Q036 | monitoring | operational | recommended | Minimum sample volume | drinking water | To obtain a reliable estimate of the number of E. coli in treated drinking water, a minimum volume of 100 mL of water should be analyzed. | Treated drinking water analysis | high |
| #Q037 | monitoring | operational | recommended | Weekly testing of plant effluent and distribution system | drinking water | As part of operational and verification monitoring in a drinking water quality management system using a source-to-tap or water safety plan approach, water leaving a treatment plant and within the distribution system should be tested at least weekly for E. coli and daily for disinfectant residual and turbidity. | Operational and verification monitoring | high |
| #Q038 | monitoring | operational | recommended | Increase samples based on population | drinking water | The number of samples for bacteriological testing should be increased in accordance with the size of the population served. | Bacteriological testing | high |
| #Q039 | monitoring | operational | recommended | Concurrent disinfectant residual testing | drinking water | Disinfectant residual tests should be conducted when bacteriological samples are taken. | When bacteriological samples are taken | high |
| #Q040 | administrative | operational | mandatory | Selection of municipal sampling points | drinking water | In municipal-scale systems, the location of sampling points must be selected or approved by the responsible drinking water authority. | Municipal-scale systems | high |
| #Q041 | monitoring | operational | recommended | Appropriate sample site locations | drinking water | Sample sites should include the point of entry into the distribution system and points in the distribution systems that are representative of the quality of water supplied to the consumer. | Selecting sample sites | high |
| #Q042 | monitoring | operational | recommended | Sampling multiple sources | drinking water | If the water supply is obtained from more than one source, the location of sampling sites should ensure that water from each source is periodically sampled. | Systems with multiple water sources | high |
| #Q043 | treatment | operational | recommended | Disinfectant residual presence | drinking water | In systems with a distribution system, a disinfectant residual should be maintained at all times. | Systems with a distribution system | high |
| #Q044 | operational | health | recommended | Distribution system operations and monitoring | drinking water | Water quality in the distribution system should be regularly monitored (e.g., microbial indicators, disinfectant residual, turbidity, pH), operations/maintenance programs should be in place (e.g., water main cleaning, cross-connection control, asset management) and strict hygiene should be practiced during all water main construction, repair or maintenance to ensure drinking water is transported to the consumer with minimum loss of quality | Distribution system operations | high |
| #Q045 | monitoring | health | recommended | Private well susceptibility assessment | drinking water | In cases where an individual household obtains its drinking water from a private well, the susceptibility of the source to fecal contamination should be assessed. | Individual households using private wells | high |
| #Q046 | treatment | health | recommended | POU device coverage | drinking water | Because of the potential public health risks from the use of microbiologically-contaminated drinking water, if POU devices are used instead of a point-of-entry system, all points of water used for drinking, food and beverage preparation, hygiene or washing dishes should be equipped with point-of-use treatment devices. | If POU devices are used instead of a point-of-entry system | high |
| #Q047 | treatment | health | recommended | Liquid chlorine requirements | drinking water | Residential-scale supplies that use liquid chlorine should use hypochlorite solutions that are certified as meeting NSF/ANSI/CAN Standard 60 (NSF/ANSI/CAN, 2018b) and follow the handling and storage recommendations for hypochlorite outlined in (Health Canada, 2018b). | Residential-scale supplies using liquid chlorine | high |
| #Q048 | monitoring | operational | recommended | Treatment device verification testing | drinking water | To verify that the treatment device is effective, the system owner/operator or homeowner should periodically test both the water entering the treatment device and the treated water for E. coli and total coliforms using an accredited laboratory. | Systems with treatment devices | high |
| #Q049 | operational | operational | recommended | Treatment device maintenance | drinking water | Treatment devices should be inspected and serviced in accordance with the maintenance schedule and manufacturer's recommendations. | Systems with treatment devices | high |
| #Q050 | monitoring | health | recommended | Additional sampling during events | drinking water | Water utilities should consider additional sampling during these events (e.g., spring runoff, storms or wastewater spills). | Events that lead to changes in source water conditions | high |
| #Q051 | monitoring | operational | recommended | Sampling hygiene and site selection | drinking water | Sample collectors are also advised to carefully choose sample locations, avoiding (or alternatively disinfecting) taps subject to external contamination (e.g., close to a sink bottom or the ground) and taps of questionable cleanliness. | During sample collection | high |
| #Q052 | administrative | operational | recommended | Laboratory holding time protocols | drinking water | Water utilities should also discuss with the laboratory, the protocols for rejecting or analysing samples that exceed holding time specifications. | | high |
| #Q053 | monitoring | operational | recommended | Recording sample storage duration and temperature | drinking water | When analysis will be delayed, it is particularly important to record the duration and temperature of storage, as this information should be taken into consideration when interpreting the results. | When sample analysis is delayed | high |
| #Q054 | treatment | operational | recommended | Chloramine stability optimization | drinking water | When chloramine is used as a residual disinfectant in drinking water distribution systems, treatment processes should be optimized for chloramine stability (Cl2:NH3 weight ratio of 4.5:1 – 5:1, pH > 8.0). | When chloramine is used as a residual disinfectant | high |
| #Q055 | operational | operational | recommended | Treatment device maintenance planning | drinking water | Consumers should verify the expected longevity of the components in their treatment device according to the manufacturer's recommendations and establish a clearly defined maintenance schedule. | For residential-scale systems with treatment devices | high |
| #Q056 | administrative | operational | recommended | Analytical method consultation | drinking water | When purchasing laboratory services or selecting analytical methods for analysis to be performed in-house, water utilities should consult with the analytical laboratory or manufacturer on issues of method sensitivity, specificity and turnaround time. | When purchasing services or selecting methods | high |
| #Q057 | administrative | operational | recommended | Guideline implementation consultation | drinking water | Specific guidance related to the implementation of drinking water guidelines should be obtained from the responsible drinking water authority in the affected jurisdiction. | When implementing guidelines | high |
| #Q058 | treatment | treatment | recommended | Surface water treatment requirements | drinking water | Treatment of surface water sources or GUDI should include adequate filtration (or technologies providing an equivalent log reduction credit) and disinfection. | Surface water or GUDI sources | high |
| #Q059 | treatment | health | recommended | Groundwater virus inactivation requirements | drinking water | Treatment of groundwater sources should include a minimum 4 log (99.99%) removal and/or inactivation of enteric viruses. | Groundwater sources | high |
| #Q060 | operational | reporting | recommended | Contextual verification of quality | drinking water | When verifying the quality of treated drinking water, the results of E. coli tests should be considered together with information on treatment and distribution system performance to show that the water has been adequately treated and is therefore of acceptable microbiological quality. | During quality verification | high |
| #Q061 | administrative | operational | recommended | Authority confirmation of requirements | drinking water | Water system owners should contact the appropriate drinking water authority in the affected jurisdiction to confirm the specific requirements that apply to their system. | | high |
| #Q062 | monitoring | operational | recommended | Maximum sample holding time | drinking water | Ideally, for E. coli analysis of drinking water samples, the holding time between the collection of the sample and the beginning of its examination should not exceed 30 hours (APHA et al., 2017). | Following sample collection | high |
| #Q063 | administrative | operational | recommended | Ultrafiltration acceptability consultation | drinking water | The responsible drinking water authority in the affected jurisdiction should be contacted to confirm the acceptability and/or applicability of these units [ultrafiltration]. | When using residential-scale ultrafiltration systems | high |
| #Q064 | administrative | operational | recommended | Extended holding time consultation | drinking water | The implications of an extended holding time should be discussed with the responsible drinking water authority in the affected jurisdiction. | When sample holding times are anticipated to exceed guidelines | high |
| #Q065 | monitoring | operational | recommended | Immediate resampling upon sample rejection | drinking water | When a sample is rejected, it is recommended that utilities immediately collect and submit a resample from that test location. | When a laboratory rejects a sample due to holding time or other criteria | high |
| #Q066 | administrative | operational | recommended | Onsite testing consultation | drinking water | Water utilities should first consult with the responsible drinking water authority about the acceptability of this practice and any other requirements that may apply. | When anticipating the use of onsite testing with commercialized test methods | high |
| #Q067 | treatment | treatment | mandatory | Treatment target point of achievement | drinking water | It is essential that the removal and inactivation targets are achieved before drinking water reaches the first consumer in the distribution system. | | high |
| #Q068 | operational | operational | mandatory | Process control and operator training | drinking water | Adequate process control measures and operator training are also required to ensure the effective operation of treatment barriers at all times. | | high |
| #Q069 | corrective_action | health | recommended | Alternative water source consideration | drinking water | If the problem cannot be corrected, additional treatment or a new source of drinking water should be considered. | When corrective actions fail to resolve contamination in residential-scale supplies | high |
| #Q070 | corrective_action | operational | recommended | Post-shock-chlorination investigation | drinking water | If the water remains contaminated after shock-chlorination, further investigation into the factors likely contributing to the contamination should be carried out. | If contamination persists after shock-chlorination in undisinfected wells | high |
| #Q071 | administrative | operational | recommended | Well construction consultation | drinking water | The responsible drinking water authority in the affected jurisdiction should be consulted regarding their specific requirements for well construction and maintenance. | For residential-scale systems | high |
| #Q072 | operational | operational | recommended | Flushing technique selection | drinking water | It is therefore important that water utilities identify and implement the most appropriate flushing technique for addressing the particular microbiological water quality issue of concern. | During distribution system maintenance or response to contamination | high |
| #Q073 | reporting | health | guidance | Pre-confirmation notification option | drinking water | the owner/operator or the responsible authority may decide to notify consumers immediately to boil their drinking water or use an alternative supply known to be safe and initiate corrective actions without waiting for confirmation. | When E. coli is detected in the first sampling | high |
| #Q074 | corrective_action | operational | guidance | Shock chlorination for UV systems | drinking water | For systems where the disinfection technology does not leave a disinfectant residual, such as ultraviolet (UV), it may be necessary to shock chlorinate the well and plumbing system. | For residential-scale systems without a disinfectant residual | high |
| #Q075 | administrative | health | recommended | Residential surveillance cooperation | drinking water | The owner/operator should also cooperate with the responsible authorities in any surveillance for possible waterborne disease outbreaks. | Following E. coli detection in a residential-scale system serving the public | high |
| #Q076 | operational | operational | recommended | Dechlorination consultation (residential disinfected) | drinking water | The responsible authority should be consulted regarding the correct procedure for dechlorinating water that may be discharged into the environment. | When increasing disinfectant dosage and flushing residential disinfected systems | high |
| #Q077 | operational | operational | recommended | Dechlorination consultation (residential undisinfected) | drinking water | The responsible authority should also be consulted regarding the correct procedure for dechlorinating water that may be discharged to the environment. | During flushing of shock-chlorinated undisinfected wells | high |
| #Q078 | treatment | treatment | recommended | Residential surface water treatment recommendation | drinking water | In general, surface water is not recommended as a residential-scale water supply unless it is properly filtered, disinfected and monitored for water quality. | For individual households or small residential supplies | high |
| #Q079 | design | treatment | recommended | UV system installation clarity | drinking water | UV systems certified to NSF/ANSI Standard 55 Class A... should be installed in visually clear water. | Installation of Class A UV disinfection systems | high |