Public Water System Compliance with the Revised Total Coliform Rule

PWSs must follow a RIDOH-approved, current coliform sampling plan to meet sampling requirements and to make sure drinking water is tested appropriately. The purpose of the PWS’s coliform sampling plan is to show where and how many water samples must be taken for total coliform monitoring. The sampling plan includes a coliform sampling schedule, requiring total coliform sampling on a monthly or quarterly basis. The circumstances outlined in the Coliform Sampling Schedule Changes section below can cause a change to a PWS’s total coliform sampling frequency. For the latest sampling schedules and results, visit Drinking Water Viewer. Instructions for using Drinking Water Viewer are available here.

The sampling plan is helpful when a water sample result shows total coliforms are present because it will show where additional required samples need to be collected. Repeat sampling helps to confirm if there is a pathway for microbial contamination within the water system. For more information about properly labeling and submitting the samples to your lab to ensure that results are reported accurately, refer to the Drinking Water Sample Reporting Codes guidance.

If your coliform sampling plan needs to be updated, contact the Rhode Island Department of Health (RIDOH) Center for Drinking Water Quality (DWQ) at 401-222-6867 or email DOH.RIDWQ@health.ri.gov with a subject line containing, “Coliform sampling plan,” name of PWS, and PWS ID number.

What to Do When a Sample Shows Total Coliforms Are Present

A combination of routine and repeat water samples will confirm the presence or absence of total coliforms or E. coli bacteria in the PWS’s distribution system. Download and print the PWS Routine Monitoring for Coliform Bacteria guidance document. This document includes a flowchart that illustrates the sampling process and what actions to take when sample results show that total coliforms or E. coli are present. It is designed to help you put your coliform sampling plan into action. Note: If your PWS takes 40 samples or more per month, parts of the process are different. Contact RIDOH with any questions.

Do not disinfect the water system or increase existing disinfection before collecting repeat, routine, or triggered well samples unless directed to do so by RIDOH.

Well Sampling for Total Coliforms

Total Coliforms Are Present in Well (but E. coli Is Absent), Follow-Up Sampling, and Disinfection

Use this section as guidance when a well sample result shows that total coliforms are present and the result is not from a triggered well sample that was taken because total coliforms were present in the distribution system. A PWS must issue a boil water notice if they receive E.coli-present sample results from a well that does not have RIDOH-approved 4-log disinfection treatment. To read more about required boil water orders, go to the Emergency Information for Public Water Systems webpage.

If sample results from a PWS’s well show total coliforms are present and sample results from the primary sampling location listed on the coliform sampling plan show total coliforms are absent, the PWS must take a follow-up sample from the primary sampling location within 24 hours. This is a follow-up routine sample, not a repeat sample.

Total Coliforms Are Absent in Follow-Up Routine Sample Results

If the follow-up routine sample results show total coliforms are absent, the well must be disinfected, pumped to waste, and another well sample must be collected to ensure successful disinfection. If the PWS has more than one well, the affected well must be shut off if possible before the PWS proceeds with disinfection, pumping to waste, and sampling the well. Once sample results showing that total coliforms are absent are received by RIDOH and are satisfactory, the PWS will receive approval to place the well back into service.

Total Coliforms Are Present in Follow-Up Routine Sample Results

If the follow-up routine sample results show totals coliform are present, the PWS must conduct repeat sampling and triggered well sampling as required. Use the Well Disinfection Procedure and save it for reference during compliance inspections.

Boil water notices are issued by PWSs to customers when water quality is or is potentially compromised and unsafe. To read more about precautionary boil water notices, the conditions that cause a boil water notice, and the PWS’s responsibilities for the duration of the boil water notice go to the Emergency Information for Public Water Systems webpage.

If an E. coli MCL violation occurred, RIDOH must be notified by the end of the day on which the PWS learns of the violation. Call the office at 401-222-6867 or email DOH.RIDWQ@health.ri.gov with the name of PWS, and PWS ID number in the subject line.

If a PWS loses pressure or “dewaters”, RIDOH must be notified within 24 hours of the dewatering event. Call the office at 401-222-6867 or email DOH.RIDWQ@health.ri.gov with the name of PWS, and PWS ID number in the subject line.

The Public Water Emergency Information for Consumers webpage is meant to be shared with water customers during and after the implementation of a boil water order.

Circumstances that Cause Sampling Schedules to Increase from Quarterly to Monthly

A PWS’s monitoring schedule will be increased from quarterly to monthly if the water system

• Triggers a level 2 assessment (L2A) or a second level 1 assessment (L1A) in a rolling 12-month period;
• Has an E. coli maximum contaminant level violation;
• Has a coliform treatment technique violation;
• Has 2 coliform monitoring violations in a rolling 12-month period; or
• Has 1 coliform monitoring violation and has triggered one L1A in a rolling 12-month period.

Non-Community Water Systems Can Request to Reduce Sampling from Monthly to Quarterly

Groundwater PWSs that serve fewer than 1,000 people, are on monthly sampling schedules, and meet all the criteria below may be eligible for reduced total coliforms monitoring. The PWS must show that it has all of the following

• Ownership of the 200-foot radius of land around a drilled well or 400-foot radius of land around a gravel packed well that is protected with no sources of contamination (i.e., septic systems, leach fields, etc.);
• All wells meet approved construction standards;
• A clean compliance history for a rolling 12-month period prior to the request (i.e., no monitoring violations, treatment technique violations, or triggers, etc.); and
• A sanitary survey or voluntary L2A (performed by a State-certified Level 2 Assessor) within the last 12 months that demonstrates that the PWS is free of sanitary defects.

The criteria in this section are compiled from the regulations for Public Drinking Water 1.17.1(A)(5)(a). Community water systems have different requirements for reduced monitoring. Contact RIDOH with any questions.

All seasonal and partially seasonal water systems must choose opening and closing dates, follow the procedures found in the water system’s Seasonal Start-up Plan, and certify that they have verified the sanitary condition of the system before water is served to the public (including staff and workers). The Seasonal Start-up Form and required sample results must be submitted to RIDOH before the opening date. See the Seasonal Start-up Kit for guidance about the seasonal start-up process, including important reminders, a helpful checklist, and Frequently Asked Questions. For more information about total coliform sampling, refer to the section Coliform Sampling Plan. RIDOH recommends that PWSs complete start-up procedures one to two weeks before the opening date.

All seasonal and partially seasonal systems are required to follow their monitoring schedules, which can be found on Drinking Water Viewer. View instructions for using Drinking Water Viewer by clicking here. Required samples must be collected while the water system is open and active. RIDOH issues reminders for sampling and procedure requirements. Follow the links below to view some example reminders:

• First month of the quarter sampling
• Annual well sampling
• Seasonal shut-down requirements

RIDOH has developed a webinar for seasonal public water systems to use at the start of the season. The webinar covers start-up procedures, including preparing to start-up, inspecting the system, disinfection and flushing, and sample collection and submitting results. Watch the recording and download the slide deck using the links below. Certified operators please note: RIDOH will offer a training on this topic once per year, and attendees can receive certified operator training credit hours.

• Webinar recording
• Slide deck