| #Q001 | monitoring | operational | recommended | Distribution System Monitoring | drinking water | Total coliforms should be monitored in the distribution system because they are used to indicate changes in water quality. | Applicable to distribution systems | high |
| #Q002 | corrective_action | operational | recommended | Investigation of Total Coliform Detections | drinking water | Detection of total coliforms from consecutive samples from the same site or from more than 10% of the samples collected in a given sampling period should be investigated. | Consecutive samples from same site OR >10% of samples positive | high |
| #Q003 | monitoring | operational | recommended | Multi-Barrier Approach Monitoring | drinking water | Monitoring for total coliforms should be used, in conjunction with other indicators, as part of a multi-barrier approach to producing drinking water of an acceptable quality. | | high |
| #Q004 | corrective_action | health | recommended | Well Water Trigger Actions | drinking water | As their presence indicates that the groundwater may be vulnerable to contamination from the surrounding environment, detection of total coliforms in the water leaving the well should trigger further actions. | Detection of total coliforms in protected groundwater leaving a well | high |
| #Q005 | corrective_action | health | mandatory | Response to Treatment Plant Positive Samples | drinking water | The presence of total coliforms in water leaving any treatment plant signifies that inadequate treatment has taken place and therefore additional actions need to be taken. These should include actions such as notifying the responsible authorities, investigating the cause of the contamination, and implementing corrective actions; which could include issuing a boil water advisory. | Presence of total coliforms in water leaving any treatment plant | high |
| #Q006 | corrective_action | health | recommended | Municipal Follow-up Actions | drinking water | In municipal-scale systems, the detection of more than 10% of samples in a given sampling period, or of consecutive samples from the same site, that are positive for total coliforms indicates changes in the quality of the water and a need for follow-up actions to be initiated. | In municipal-scale systems where water tested immediately post-treatment is free of total coliforms | high |
| #Q007 | corrective_action | health | recommended | Residential Follow-up Actions | drinking water | In residential-scale systems where there is little or no distribution system, the presence of any total coliforms should trigger follow-up actions to investigate the cause of the positive results. | Residential-scale systems | high |
| #Q008 | monitoring | operational | recommended | Treatment Plant Testing Frequency | drinking water | As a minimum, water leaving a municipal scale treatment plant should be sampled and tested at least weekly for total coliforms as part of the verification process in a source-to-tap multi-barrier approach. | Municipal scale treatment plant | high |
| #Q009 | monitoring | operational | recommended | Distribution System Sampling Quantity | drinking water | In a distribution system, the number of samples for this bacteriological testing should be increased in accordance with the size of the population served, and the samples should be taken at regular intervals throughout the month. | Distribution systems | high |
| #Q010 | monitoring | operational | recommended | Small System Sampling Frequencies | drinking water | Sampling frequencies in residential-scale and small private systems may vary from jurisdiction to jurisdiction but should include times when the risk of contamination is greatest, for example, after spring thaw, heavy rains, or dry periods. | Residential-scale and small private systems | high |
| #Q011 | monitoring | operational | recommended | New or Rehabilitated Well Testing | drinking water | New or rehabilitated wells should also be sampled initially to confirm acceptable bacteriological quality. | New or rehabilitated wells | high |
| #Q012 | operational | operational | mandatory | Sample Collection Procedures | drinking water | Proper procedures for collecting samples must be observed to ensure that the samples are representative of the water being examined. | | high |
| #Q013 | monitoring | operational | recommended | Sample Volume and Test Initiation | drinking water | A minimum volume of 100 mL of water should be collected for testing, and testing should be started as soon as possible after collection. | | high |
| #Q014 | treatment | treatment | recommended | Minimum Treatment for Surface or GUDI Sources | drinking water | Generally, minimum treatment of supplies derived from surface water or GUDI sources should include filtration (or technologies providing an equivalent log reduction credit) and disinfection. | Surface water or GUDI sources | high |
| #Q015 | treatment | treatment | recommended | Treatment for Protected Groundwaters | drinking water | Protected groundwaters should receive adequate treatment for the removal/inactivation of enteric viruses, unless exempted by the responsible authority based on site-specific considerations, such as historical and on-going monitoring data. | Protected groundwater sources | high |
| #Q016 | treatment | operational | recommended | Disinfectant Residual Maintenance | drinking water | In systems with a distribution system, a disinfectant residual should be maintained at all times. | Systems with a distribution system | high |
| #Q017 | administrative | operational | recommended | Guideline Implementation Consultation | drinking water | Specific guidance related to the implementation of drinking water guidelines should be obtained from the appropriate drinking water authority in the affected jurisdiction. | | high |
| #Q018 | monitoring | operational | recommended | Municipal Treatment Plant Weekly Monitoring | drinking water | Total coliforms should be monitored at least weekly in water leaving a treatment plant. | Municipal scale drinking water supply systems | high |
| #Q019 | monitoring | operational | recommended | Municipal Distribution System Minimum Samples | drinking water | In municipal scale distribution and storage systems, the number of samples collected for total coliform 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 |
| #Q020 | reporting | health | recommended | Treatment Breach Corrective Action and Notification | drinking water | This situation should be corrected immediately. The system owner should notify all responsible authorities and immediately reanalyze the coliform-positive sample(s) for Escherichia coli and resample and test the positive site(s) to confirm the presence or absence of both E. coli and total coliforms (see Appendix A). | Detection of total coliform bacteria in water leaving a treatment plant | high |
| #Q021 | corrective_action | health | recommended | Distribution System Investigation Trigger | drinking water | Detection of total coliforms (in the absence of E. coli) in more than 10% of samples in a given sampling period, or from consecutive samples from the same site, should be investigated and appropriate corrective actions taken. | Distribution system | high |
| #Q022 | administrative | health | recommended | Response Discussion with Agencies | drinking water | The degree of response to the presence of total coliforms (in the absence of E. coli) should be discussed with the appropriate agencies and will depend on a risk-based assessment of the significance and extent of the problem... | | high |
| #Q023 | corrective_action | operational | recommended | Corrective Action: Verify Treatment Process | drinking water | If corrective actions are deemed necessary, the owner of the waterworks system, in consultation with the responsible authorities, should carry out appropriate corrective actions, which could include the following measures: Verify the integrity and the optimal operation of the treatment process. | If corrective actions are deemed necessary | high |
| #Q024 | corrective_action | operational | recommended | Corrective Action: Verify Distribution System | drinking water | If corrective actions are deemed necessary, the owner of the waterworks system, in consultation with the responsible authorities, should carry out appropriate corrective actions, which could include the following measures: Verify the integrity of the distribution system. | If corrective actions are deemed necessary | high |
| #Q025 | corrective_action | operational | recommended | Corrective Action: Verify Disinfectant Residual | drinking water | If corrective actions are deemed necessary, the owner of the waterworks system, in consultation with the responsible authorities, should carry out appropriate corrective actions, which could include the following measures: Verify that the required disinfectant residual is present throughout the distribution system. | If corrective actions are deemed necessary | high |
| #Q026 | corrective_action | operational | recommended | Corrective Action: Disinfectant Dosage and Flushing | drinking water | If corrective actions are deemed necessary, the owner of the waterworks system, in consultation with the responsible authorities, should carry out appropriate corrective actions, which could include the following measures: Increase the disinfectant dosage, flush the water mains, clean treated-water storage tanks (municipal reservoirs and domestic cisterns), and check for the presence of cross-connections and pressure losses. | If corrective actions are deemed necessary | high |
| #Q027 | operational | operational | recommended | Dechlorination Before Discharge | drinking water | Water should be dechlorinated before being discharged into fish-bearing waters. The responsible authority should be consulted regarding the methods available, as well as the correct procedure, for carrying out dechlorination. | Flushing operations discharging into fish-bearing waters | high |
| #Q028 | monitoring | operational | recommended | Corrective Action: Adjacent Sampling | drinking water | If corrective actions are deemed necessary, the owner of the waterworks system, in consultation with the responsible authorities, should carry out appropriate corrective actions, which could include the following measures: Sample and test sites adjacent to the site(s) of the positive sample(s). Tests performed should include total coliforms, E. coli , disinfectant residual, and turbidity. At a minimum, one sample upstream and one downstream from the original sample site(s) plus the finished water from the treatment plant as it enters the distribution system should be tested. Other samples should be collected and tested following a sampling plan appropriate for the distribution system. | If corrective actions are deemed necessary | high |
| #Q029 | corrective_action | operational | recommended | Corrective Action: Investigate Cause | drinking water | If corrective actions are deemed necessary, the owner of the waterworks system, in consultation with the responsible authorities, should carry out appropriate corrective actions, which could include the following measures: Conduct an investigation to identify the problem and prevent its recurrence, including a measure of raw water quality (e.g., bacteriology, colour, assimilable organic carbon [AOC], turbidity, conductivity) and variability. | If corrective actions are deemed necessary | high |
| #Q030 | monitoring | operational | recommended | Corrective Action: Continue Selected Sampling | drinking water | If corrective actions are deemed necessary, the owner of the waterworks system, in consultation with the responsible authorities, should carry out appropriate corrective actions, which could include the following measures: Continue selected sampling and testing (e.g., bacteriology, disinfectant residual, turbidity) of all identified sites during the investigative phase to confirm the extent of the problem and to verify the success of the corrective actions. | During investigative phase | high |
| #Q031 | administrative | health | recommended | Boil Water Advisory Discussion | drinking water | If enhanced health surveillance indicates that a waterborne outbreak may be occurring or if conditions exist that could result in a waterborne outbreak, then the necessity of issuing a boil water advisory should be discussed immediately with senior operations personnel at the water utility and with the responsible authority. | Indications or risks of a waterborne outbreak | high |
| #Q032 | reporting | health | recommended | Immediate Consumer Notification | drinking water | In the event that an incident that may have contaminated the distribution system or interfered with treatment is known to the owner, consumers should be notified immediately to boil the drinking water. | Known incident affecting distribution system or treatment | high |
| #Q033 | administrative | health | mandatory | Conditions to Rescind Boil Water Advisory | drinking water | A boil water advisory should be rescinded only after a minimum of two consecutive sets of samples, collected 24 hours apart, show negative results that demonstrate full system-wide integrity (including acceptable bacteriological quality, disinfection residuals, and/or turbidity). | Rescinding a boil water advisory | high |
| #Q034 | design | treatment | recommended | Treatment Fluctuation Adaptation | drinking water | The appropriate type and level of treatment should take into account the potential fluctuations in water quality, including short-term water quality degradation, and variability in treatment performance. | | high |
| #Q035 | administrative | operational | mandatory | Residential Scale Jurisdictional Sampling | drinking water | Sampling frequencies for residential-scale systems will be determined by the authority having jurisdiction for the system and should include times when the risk of contamination is greatest, for example, early spring after the thaw, after an extended dry spell, or following heavy rains. | Residential-scale systems | high |
| #Q036 | monitoring | health | recommended | Private Supply Testing Recommendation | drinking water | Owners of private supplies should be encouraged to have their water tested for total coliforms during these same periods. | Private supplies | high |
| #Q037 | monitoring | health | recommended | New or Rehabilitated Well Testing Residential | drinking water | New or rehabilitated wells should also be tested before use to confirm the microbiological quality. | New or rehabilitated wells | high |
| #Q038 | monitoring | health | recommended | Immediate Reanalysis for Residential Systems | drinking water | If a sample contains total coliform bacteria, it should be immediately reanalyzed and the positive site resampled and tested to confirm the presence or absence of both E. coli and total coliforms. | Positive sample in residential scale water supplies | high |
| #Q039 | corrective_action | health | mandatory | Investigation of Coliform Source Residential | drinking water | Regardless of whether a boil water advisory is issued, the source of the coliforms needs to be investigated, and appropriate actions need to be taken (see Appendix B). | Detection of coliforms in residential systems | high |
| #Q040 | corrective_action | operational | mandatory | Sanitary Survey for Disinfected Supplies | drinking water | The first step is to conduct a sanitary survey to verify 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, and surrounding area. Any identified faults should be corrected before proceeding. | Positive total coliform sample in disinfected residential supplies | high |
| #Q041 | corrective_action | operational | recommended | Corrective Actions in Chlorinated Systems | drinking water | In a chlorinated system, verify that a disinfectant residual is present throughout the system. Increase the disinfectant dosage, flush the system thoroughly, and clean treated-water storage tanks and domestic cisterns. Water should be dechlorinated before being discharged to fish-bearing waters. The responsible authority should be consulted regarding the methods available, as well as the correct procedure, for carrying out dechlorination. | Chlorinated residential systems needing corrective action | high |
| #Q042 | corrective_action | operational | guidance | Shock Chlorination for Non-residual Systems | drinking water | For systems where the disinfection technology does not leave a disinfectant residual, such as UV or ozone, it may be necessary to shock chlorinate the well and plumbing system | Systems without disinfectant residual | medium |
| #Q043 | operational | operational | mandatory | Disinfection System Maintenance Verification | drinking water | Ensure that the disinfection system is working properly and maintained according to manufacturer's instructions. | | high |
| #Q044 | monitoring | health | recommended | Post-Correction Sampling Residential | drinking water | After the necessary corrective actions have been taken, samples should be collected and tested for both total coliforms and E. coli to confirm that the problem has been corrected. | Post-corrective actions in residential systems | high |
| #Q045 | corrective_action | health | recommended | Actions if Disinfected System Remains Positive | drinking water | If total coliforms are detected after implementing these corrective actions, a boil water advisory should be issued, if one is not already in place. Alternatively, a source of water known to be safe should be used until the situation is corrected. | If positive results persist after corrective actions | high |
| #Q046 | treatment | health | recommended | Consideration of Additional Treatment or New Source | drinking water | If the problem cannot be corrected, additional treatment or a new source of drinking water may need to be considered. | Persistent vulnerability to contamination | high |
| #Q047 | corrective_action | operational | recommended | Sanitary Survey for Non-Disinfected Wells | drinking water | The first step, if it has not already been taken, is to conduct a sanitary survey to verify the physical condition of the well, well head, pump, plumbing, and surrounding area. Any identified faults should be corrected before proceeding. | Positive sample in non-disinfected wells | high |
| #Q048 | corrective_action | operational | recommended | Shock Chlorinate Non-Disinfected Well | drinking water | Shock-chlorinate the well and plumbing system. | After correcting physical faults in a non-disinfected well | high |
| #Q049 | corrective_action | operational | recommended | Flush and Retest Non-Disinfected Well | drinking water | Flush the system thoroughly and retest to confirm that the water is free of total coliform contamination. Confirmatory tests should be done no sooner than either 48 hours after tests indicate the absence of a chlorine residual or 5 days after the well has been treated. | Following shock-chlorination | high |
| #Q050 | corrective_action | health | recommended | Actions if Non-Disinfected Well Remains Positive | drinking water | If total coliforms are detected after implementing these corrective actions, a boil water advisory should be issued, if one is not already in place. Alternatively, a source of water known to be safe should be used until the situation is corrected. | If total coliforms are detected after implementing corrective actions in a non-disinfected well | high |
| #Q051 | design | treatment | recommended | Well Reconstruction or Replacement | drinking water | If the problem cannot be reasonably identified or corrected, an appropriate disinfection device or well reconstruction or replacement should be considered. | Persistent well contamination | high |
| #Q052 | monitoring | health | recommended | Minimum Consecutive Negative Samples Requirement | drinking water | A single negative total coliform test result does not necessarily indicate that the problem has been corrected. A minimum of two consecutive total coliform negative samples should be obtained. | Confirming correction of contamination | high |
| #Q053 | monitoring | operational | recommended | Long-Term Verification Testing | drinking water | An additional test should be taken after 3-4 months to ensure that the contamination has not recurred. | Following successful corrective action in a non-disinfected well | high |
| #Q054 | administrative | operational | mandatory | Authority Prescription of Distribution Monitoring | drinking water | The sampling points and testing frequencies for total coliforms, residual disinfectant, and turbidity in treated water within distribution and storage systems will be prescribed by the responsible authority. | Municipal scale distribution and storage systems | high |
| #Q055 | operational | operational | recommended | Distribution Monitoring Strategy Design | drinking water | The approach should take into account the particular characteristics of the distribution and storage system and historic knowledge of the overall system such as age, layout, or materials. | Development of a distribution and storage system monitoring strategy | high |
| #Q056 | administrative | operational | mandatory | Authority Prescription of Treatment Plant Testing | drinking water | While the required frequency for all testing at the treatment plant is prescribed by the responsible authority, best practice commonly involves a testing frequency beyond these minimum recommendations based upon the size of system... | Monitoring water leaving the treatment plant | high |