Revised Total Coliform Rule
Since 1992, all community water systems have been operating under the Total Coliform Rule (TCR) that required monthly microbiological monitoring of your drinking water. EPA has made changes to this rule that will affect the operation of your water system. This new rule is referred to as the Revised Total Coliform Rule (RTCR). The RTCR is in effect as of April 1, 2016. There are four major areas of concern for your system as follows-
Sampling-Under the RTCR, all systems will submit ROUTINE monthly microbiological sample(s). They will be tested for TOTAL COLIFORMS and for E.COLI if total coliforms are present. If total coliforms are present, all systems will collect THREE REPEAT samples within 24 hours of notification of the positive sample. The additional routine sampling in the month following a positive sample for systems less than 4100 people has now been eliminated. Anytime a routine or repeat sample is E.COLI positive, the system must contact the Drinking Water Program (DWP. The DWP phone numbers are (605) 773-3754 or (605) 280-6831 on weekends.
Sample Site Plans-Your system at some time in the past has submitted to DENR a sampling plan that designated where you would be taking your ROUTINE samples. By March 31, 2016, you must submit an updated sampling plan that designates all of your ROUTINE, REPEAT, and GROUNDWATER RULE TRIGGERED (if applicable) sampling sites. The repeat sample sites will remain as they did under the old TCR except there is no longer a fourth sample needed for systems serving less than 1000 people. The repeat sample sites are-
- One sample from the site of the original unsafe routine sample
- One sample from within five service connections downstream of the original unsafe routine sample
- One sample from within five service connections upstream of the original unsafe routine sample
On your sampling plans, you will need to designate these repeat sample sites for each of your routine sample sites. The sampling plan must be submitted to DENR for review and revision. Water systems have received information on updating sample plans previously.
Violations-Under the old TCR if your water system had more than one positive sample in a month, it was considered as a violation of the Safe Drinking Water Act, and you were required to issue a public notice. Under the RTCR, this is not a violation but is now called a TREATMENT TECHNIQUE TRIGGER. You do not have to issue a public notice but do have to do an assessment of your water system to determine what possibly caused the positive samples (please see next section on Assessments and Corrective Actions). If you do not perform the assessment and submit the report to DENR, this is a treatment technique violation that requires public notice.
There is still the E. coli acute violation that requires a Tier I public notice within 24 hours. This violation occurs when any of the following situations happen-
- E. coli-positive repeat sample
- E. coli-positive routine sample followed by a total coliform-positive repeat sample.
- E. coli-positive routine sample and system fails to take all required repeat samples.
- Total coliform-positive repeat sample and the lab fails to further test for E. coli.
You must contact the Drinking Water Program to consult on the Tier I public notice within 24 hours. The DWP phone numbers are (605) 773-3754 or (605) 280-6831 on weekends.
Assessments and Corrective Actions-Under the old TCR if you had more than one positive sample in a month, the only action you had to take was to issue your public notice. Under the RCTR, there are several situations when you will conduct a self-assessment of your water system to determine what caused the positive samples. This is called a Level 1 Assessment. The following situations require a Level 1 Assessment-
- More than one positive sample in a month
- More than 5% positive samples in a month (RC/SF only)
- Failure to take all required repeat samples
An assessment must be done, and a report submitted to DENR within 30 days. DENR will be developing a form to follow when doing this assessment. If any sanitary defects are found in the system as a result of the assessment, these must then be corrected within the 30 days or corrected within a schedule agreed upon with DENR.
The RTCR requires that a Level 1 Assessment include a review of the following elements:
- Inadequacies in sample sites, sampling protocol, and sample processing.
- Atypical events that may have affected distributed water quality or indicate that distributed water quality was impaired.
- Changes in distribution system maintenance and operation that may have affected or are affecting distributed water quality, including water storage.
- An evaluation of source water quality and treatment changes or conditions that may affect distributed water quality, where appropriate.
- Existing water quality monitoring data.
A Level 2 Assessment is similar to a Level 1 except it examines the water system in more detail. The following situations require a Level 2 Assessment to be performed-
- An E. coli acute violation
- A second Level 1 Treatment Technique Trigger within a 12 month period
The Level 2 Assessments may be performed by DENR, designated third parties, or the water system itself if there are operators with certain certifications and qualifications. DENR will determine who can conduct Level 2 Assessments.
For more information on the Revised Total Coliform Rule and Sampling Plan Requirements: