Revised Total Coliform Rule

The Revised Total Coliform Rule (RTCR) replaced the Total Coliform Rule on April 1, 2016. It requires systems vulnerable to contamination to find and fix problems and pathways that could allow pathogens to enter the distribution system.

We have always required water systems to look for maintenance or operational defects that could allow contamination to enter a system. RTCR formalizes the process. It requires water systems to assess their entire system—from sample collection point to source of supply—and submit an assessment report to us within 30 days after specific “trigger” events occur.

Required Monitoring

Water systems will continue to collect the same number of samples at the same frequency as previously required under the Total Coliform Rule. See your Water Facilities Inventory (WFI) form for your system’s monitoring schedule.

RTCR requires all water systems to collect 3 repeat samples for every total coliform-present routine sample. Systems should outline the locations of the repeats in their Coliform Monitoring Plan. Our Follow-up to an Unsatisfactory Routine Coliform Sample 331-187 (PDF) details the location. 

Failure to collect the required repeat samples results in further follow-up action. If a system fails to collect three repeat samples for every total coliform-present routine sample, RTCR requires it to conduct a water system assessment.

RTCR does not allow any system to use a source sample as both a repeat sample and a groundwater source sample. Instead, the rule requires all systems to collect a raw water sample from each groundwater source that was in use on the day they collected the routine sample, in addition to the three repeat samples.

RTCR requires water systems to collect their normal number of routine samples the month after a total coliform-present routine sample. Very small noncommunity groundwater systems not required to sample every month must collect ONE ROUTINE sample the month following an unsatisfactory sample even if they normally would not be required to collect a sample that month.

RTCR introduced a provision for very small noncommunity groundwater systems to be able to maintain a non-monthly routine sampling requirement. These systems must maintain a clean compliance history for a minimum of 12 months. “Clean compliance history” means a record of no E. coli MCL violations; no monitoring violations; and no coliform treatment technique triggers exceedances or treatment technique violations. 

Treatment Technique Trigger Assessments

A treatment technique trigger is a situation that requires a water system to take action. RTCR requires water systems to conduct an assessment to “find and fix” any sanitary defects whenever a treatment technique trigger occurs. There are two assessment levels. Both evaluate the entire system from the sample collection point to the source of supply.

You should anticipate that a treatment technique trigger might occur any time you collect routine and repeat samples. Therefore, you should be ready to start a system evaluation as soon as the lab notifies you of total coliform-present results, which trigger the assessment requirement.

Don’t wait to hear from us. You must complete a Level 1 and Level 2 assessment within 30 days after the treatment trigger occurs.

Level 1 Assessment

A basic water system evaluation an owner, manager, or other knowledgeable person can do. A Level 1 treatment technique trigger occurs any time a water system:

  • Collects few than 40 routine samples a month and has two or more total coliform-present results the same month.
  • Collects 40 or more routine samples a month and has total coliform-present results in more than 5 percent of its routine and repeat samples.
  • Fails to collect three repeats for every total coliform-present routine sample.

Level 2 Assessment

A complex evaluation that only a person with state-required qualifications can do. A Level 2 treatment technique trigger occurs when a water system has:

  • An E. coli MCL violation.
  • A second Level 1 treatment technique trigger within a rolling 12-month period.

Sanitary Defects and Defects

RTCR distinguishes between “sanitary defects” and “defects.” Either might cause a total coliform-present sample, which triggers the assessment requirement.

Sanitary defect: A pathway for contaminants to enter the water system or the failure or imminent failure of an existing barrier. 

Defect: An issue identified during an assessment that could have caused total coliform-present samples, such as using an improper sample collection technique.

Seasonal Water Systems

RTCR recognizes a new noncommunity seasonal water system. RTCR’s seasonal system doesn’t operate year-round, totally depressurizes the water lines at the end of each operating season, and has at least one month when it serves no people.

Complete system shutdown creates opportunities for contamination to enter or spread through the distribution system. Therefore, all seasonal water systems must:

  • Have a state-approved start-up procedure.
  • Follow the procedure before opening for the season each year.
  • Send us a certificate declaring that they followed the procedure before serving water to the public.

Failure to do so is a treatment technique violation, which requires public notification to water system customers.

Violation Types

There are three RTCR violation types. 

Treatment Technique Violations

RTCR requires public notification within 30 days when a:

  • Water system fails to conduct a required Level 1 or Level 2 assessment within 30 days of learning about the treatment technique trigger.
  • Water system fails to correct a sanitary defect identified in a Level 1 or Level 2 assessment within 30 days of learning about the treatment technique trigger.
  • Seasonal system fails to complete state-approved startup procedures before providing water to customers.

Monitoring Violations

  • A water system fails to collect every routine sample.
  • A lab fails to test a total coliform-present routine sample for E. coli.

Reporting Violations

  • Water system fails to submit a monitoring report or completed assessment report in a timely manner.
  • Water system fails to notify us of an E. coli- present sample in a timely manner.
  • Seasonal system fails to submit certification of completion of approved start-up procedure.

Helpful Hints

Preventing contamination is the best strategy for protecting public health. You can quickly assess and take corrective action by:

  • Conducting routine surveillance of your facilities.
  • Using standard operating procedures and keeping them current.
  • Learning the scope of both assessments and knowing when you must use them.
  • Good sample collection technique can reduce the possibility of having a total coliform-present sample.
  • Make sure to collect every routine and repeat sample.
  • Find and fix any sanitary defects as soon as you are aware of them.
  • Remember to send us your completed Level 1 and Level 2 assessment documentation.

If you are a seasonal water system, remember to follow your start-up procedure before providing water to the public at the beginning of each new season.

For More Information

Contact Us

Northwest Regional Office, Kent
Coliform Program: 253-395-6754 Main Office: 253-395-6750

Southwest Regional Office, Tumwater
Coliform Program: 360-236-3030 Main Office: 360-236-3030

Eastern Regional Office, Spokane
Coliform Program: 509-329-2134 Main Office: 509-329-2100