Revised Total Coliform Rule

The federal Safe Drinking Water Act (SDWA) requires that all public water systems (community and noncommunity) provide an adequate supply of safe drinking water to customers and consumers.  The Michigan Department of Environmental Quality (DEQ) is responsible for implementing and managing the SDWA at the state level.  One of the regulations is the 1989 Total Coliform Rule (TCR). 

On April 1, 2016, the Revised Total Coliform Rule (RTCR) took effect replacing the TCR regulations.  The RTCR establishes a maximum contaminant level (MCL) for E. coli and uses E. coli and total coliforms to initiate a find-and-fix approach to address potential avenues of contamination of the distribution system. 

Guidance and Training

Sample Siting Plan - All water supplies must have a current and complete sample siting plan (SSP) on file with the DEQ.  It is the responsibility of the water supply to update the SSP if there are any changes.   A blank copy of the Sample Siting Plan can be found as a Microsoft Word Document or as an Adobe PDF document.

Bacteriological Sampling Procedure

1.

Collect samples from the DEQ-approved locations in the SSP. 

2.

Read the sampling instructions carefully.

3.

Make sure the faucet and tap are clean.  There should be no attachments on the faucet or tap.

4.

Flame or bleach the tap using a propane torch or bleach (optional - based on system's knowledge and standard practices).

5.

Run water a minimum of 5 minutes, or for time specified in sampling site plan, to flush line for fresh sample. 

6.

Remove cap from sample bottle.  Do not touch lip of bottle or inside of cap.

7.

Fill bottle to the neck, leaving an air space at the top.

8.

Recap bottle and secure cap tightly.

9.

Complete laboratory form making sure to include the Water Supply Serial Number (WSSN), sampling site ID (as it appears on the SSP), sample date and sample time.

10.

Submit sample to laboratory immediately.  The laboratory testing must begin within 30 hours of collecting the sample.

11.

If there is any deviation from the SSP, please contact the DEQ District Office. 


RTCR Monitoring Frequency for Community Water Supplies

Table 1: Total Coliform Monitoring Frequency for Community Water Supplies (pages 127 and 128).

RTCR Reporting Requirements for Community Supplies:

  • Routine monitoring results are due to the DEQ by the 10th of the following month.
  • Contact the DEQ within 24 hours of an E.coli-positive sample result.
  • Contact the DEQ after a total coliform-positive sample (recommended).

What if my system has a total coliform-positive routine sample?  Repeat and possibly triggered sampling is required.  Use the Routine Positive Flowchart for reference on how to proceed.  If you have questions, please contact the district office.

Assessments- Level 1 assessments are performed by the water supply owner or operator to identify sanitary defects that can cause contamination.  Level 2 assessments are more comprehensive and are performed by DEQ staff.  Assessments are required when treatment technique triggers occur.

A Level 1 Assessment is triggered by:

  • For supplies collecting 40 samples per month or more; >5% of routine and repeat samples in a month are total coliform-positive.
  • For supplies collecting fewer than 40 samples per month; 2 or more routine and repeat samples in a month are total coliform-positive.
  • The supply fails to take every repeat sample after a total coliform routine sample

The water supply must complete the assessment within 30 days.  A blank copy can be found in Word or PDF.

A Level 2 Assessment is triggered by:

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

Please contact your district office if you have any questions.

Presentations/Education

AWWA – Maintaining and Achieving RTCR Compliance for Small Systems

Related Links

Noncommunity Water Supply

Certified Labs for Microbiological Testing

Association of State Drinking Water Administrators

American Water Works Association

USEPA