An official website of the United States government.

This is not the current EPA website. To navigate to the current EPA website, please go to This website is historical material reflecting the EPA website as it existed on January 19, 2021. This website is no longer updated and links to external websites and some internal pages may not work. More information »

Revised Total Coliform Rule Implementation in Wyoming and on Tribal Lands in EPA Region 8

Overview of the Rule

The Revised Total Coliform Rule (RTCR) increases public health protection by reducing potential pathways for fecal contamination in the distribution system of a public water system (PWS).

As of April 1, 2016:  All PWSs in Wyoming and Indian Country in Region 8 must comply with the RTCR requirements as defined by EPA Region 8.

So what do you need to know?

Do you want to get credit for the RTCR samples that you collect each month? The most common way for samples to not be credited to your water system is when the samples are not properly labeled when sent to the lab. Such incomplete labeling results in EPA issuing dozens of RTCR Monitoring Violations each year. Don’t let that happen to you! Proper labeling of lab sample bottles and Chain of Custody forms for each Total Coliform sample collected is a critical part of staying in compliance with the National Primary Drinking Water Regulations. RTCR and GWR Sample Labeling Instructions contains a short description of the three types of samples that may be required under the RTCR. There is also information regarding source water samples that may be required under the Ground Water Rule.

Prior to April 1, 2016: All PWSs must develop and submit to EPA a written sample siting plan that identifies routine bacteriological sample locations and potential repeat sampling locations. If your system is subject to the Ground Water Rule, you must also list your source sample location in your plan. A map must also be provided along with your plan.

Link to Sample Siting Plan

  • Routine Monitoring: All PWSs in Region 8 will need to sample for Total Coliform MONTHLY. The number of required samples is based on the population of the PWS.

  • Repeat Monitoring: All PWSs must collect a set of 3 repeat samples in the distribution system following a routine total coliform positive (TC+) or E. coli positive (EC+) sample.

  • Replacement Sample Monitoring: If any routine sample submitted to the laboratory is not analyzed, you must submit a replacement. The replacement sample will need to be analyzed in the same month as the original routine sample to count for compliance.

  • Special Sample Monitoring: Special samples are still allowed and will not count toward compliance as long as they are marked appropriately prior to submission to the laboratory.

Level 1 and Level 2 Assessments

These on-site assessments are required (“triggered”) at PWSs that have been identified as having possible coliform contamination (routine sampling has shown TC+ and/or EC+ results). The PWS must fix any problems found during the assessment (these problems are identified as sanitary defects). The completed assessment form is due to EPA Region 8 as soon as possible but no later than 30 days after the system learns of the trigger. Any defects found in this assessment must also be corrected within that 30 day timeframe. If more time is needed to complete any corrective actions, the PWS can consult with EPA Region 8 and a new timeframe will be approved.

Sanitary Defect: A situation or condition that (1) could provide a pathway of entry for microbial contamination in the distribution system or; (2) is indicative of the failure or imminent failure of an existing barrier against microbial contamination that is already in place.

Level 1 Assessment: A relatively simple evaluation conducted by the PWS that reviews all areas in the water system, using an EPA Region 8 form.

How are Level 1 Assessments triggered?

  1. Having multiple TC+ samples in the same monitoring period (routines and repeats)
  2. Failure to collect ALL required repeat samples after a single TC+ sample result.

Link to L1 Assessment Form

Level 2 Assessment: A considerably more detailed assessment conducted by an EPA Region 8 approved third party. Additional sampling, inspections, etc. could be required.

How are Level 2 Assessments triggered?

  1. An E. coli MCL violation (any combination of TC+ and EC+ routines and repeats - see box below).
  2. A second Level 1 assessment triggered within a rolling 12 month period (multiple months of multiple TC+ samples).
  3. Failure to collect ALL required repeat samples after a EC+ routine sample result.

Link to L2 Assessment Form

What might constitute an E. coli MCL violation?
Routine Sample: Repeat Sample:
EC+ Any missing repeat sample
TC+ TC+ (with no E. coli analysis)

What might constitute a Treatment Technique violation?

  • Failure to complete and submit a Level 1 or 2 Assessment within 30 days of the trigger.
  • Failure to correct all sanitary defects from any assessment within 30 days of the trigger or an EPA-approved timeframe.
  • Failure of a seasonal system to conduct the start-up procedures before serving the public.

Seasonal Startup

Do you operate a seasonal system? Each year, you are required to complete and submit the Region 8 Start-up Procedure Form PRIOR to serving water to your customers for the season. Click here for the link to the Seasonal Start-up Form.