Skip to Content
Questions or Comments:

Revised Total Coliform Rule

The Revised Total Coliform Rule protects public health by reducing potential pathways for fecal and microbial contamination into public drinking water systems.

The Revised Total Coliform Rule (RTCR) uses Escherichia coli (E.coli) as a fecal indicator and establishes a maximum contaminant level (MCL) for E. coli. It also uses E. coli and total coliforms to initiate a find and fix approach to prevent fecal contamination from entering the distribution system. The RTCR requires public water systems (PWS) to identify and correct sanitary defects, and potential pathways for fecal contamination into the drinking water system.

The Environmental Protection Agency (EPA) is the primary enforcement authority and until EPA has approved the TCEQ's primacy revision application, TCEQ and EPA will share responsibility in the implementation of the RTCR. The state RTCR is in Title 30 of the Texas Administrative Code (TAC) Chapter 290 Subchapter F: Drinking Water Standards Governing Drinking Water Quality and Reporting Requirements for Public Water Systems

TCEQ regulatory guide, Coliform Monitoring, Analyzing, and Reporting Guide (RG-421), provides detailed information on coliform (total coliform and/or E. coli) compliance related to RTCR and the Groundwater Rule (GWR). EPA RTCR  provides a summary of federal drinking water requirements.

Planning and Scheduling Coliform Monitoring - Sample Siting Plan

Every public water system is required to develop a Sample Siting Plan (SSP) and distribution map. Your SSP identifies the required number of routine coliform samples per month, outlines your monthly sampling schedule, routine coliform sample locations, and repeat sample locations. The SSP is the tool to assist the PWS in collecting repeat samples within 24 hours of notification from pre-determined locations. The SSP should be reviewed and updated as changes occur in the system.

PWSs should use  TCEQ's Revised Total Coliform Rule Sample Siting Plan Template and  available in word and review the Sample Siting Plan Map Requirements and example to develop and maintain routine and repeat coliform sample locations in the distribution system. PWSs are required to attach the SSP to their Monitoring Plan and can send the SSP to or TCEQ, DWSS MC 155 - Sample Siting Plan, PO BOX 13087, Austin TX 78711-3087.

Licensing Requirements for Sample Collection

Coliform samples for the RTCR must be collected by an individual with a current water operator's license per 30 Texas Health and Safety Code, 341.034(b). An individual must have at least a class D water operator license. Transient non-community PWSs using only groundwater or purchase treated water are exempt from this requirement. TCEQ Occupational Licenses: Water System Operators webpage has more information about registration required for water operation companies and licensing for water operators.

Distribution System Coliform Samples

Coliform samples for the RTCR must be collected from the distribution system, after treatment. There are two types of compliance samples in the distribution system: routine and repeat. Both types of samples are collected the same way but serve different purposes. These samples must be reported using the Microbial Reporting Form, also called the MRF, (TCEQ Form 10525) which is provided to each PWS by the laboratory.

Guidance for Collection, Analysis, and Reporting for Microbial Contaminants under the Revised Total Coliform and Groundwater Rules (QAPP Addendum 4) is a useful resource for PWSs and laboratories. How to collect coliform samples (Video 16 minutes) is a step by step description of the sample collection process and includes helpful tips to ensure proper sample collection.  Microbial Sample Collection Example Standard Operating Procedure provides procedures for proper sample collection.

Routine Distribution Samples

All PWSs must collect routine distribution coliform samples each month to fulfill their RTCR monitoring requirement. Routine distribution samples must be collected from sites that are representative of water quality and collected at regular intervals throughout the month. The number of routine coliform samples PWSs are required to collect is based on their population. On the MRF these samples should be marked as routine.

Repeat Distribution Samples

When a PWS is notified of a total coliform positive routine distribution sample, the PWS must collect three repeat samples within 24 hours. 

  • Collect three (3) repeat samples as listed in your SSP.
    • One repeat sample from the same tap at the original site.
    • One repeat sample within five service connections upstream of the original site.
    • One repeat sample within five service connections downstream of the original site.
  • If your PWS has less than three service connections, you must still collect three repeat samples. 
  • Three repeat samples must be collected for each total coliform positive routine distribution sample.
  • Repeat samples must be marked only as “Repeat” sample type on the MRF.
  • The sample ID and date of collection of the original total coliform positive routine distribution sample must be included on the MRF.

See What To Do After You Receive A Total Coliform Positive on a Routine Distribution Sample for additional required actions and information. You can see an example and other useful information in the  RTCR Repeat Sampling Requirements Diagram.

Texas Drinking Water Public Laboratory Map

TCEQ has developed the following map to help you locate NELAP accredited public laboratories across the state of Texas that offer microbial coliform testing. Use the map below to find a laboratory near you and their contact information. Always call laboratories to confirm their address, sample drop off hours, and prices.

To find additional laboratory information, view the Texas Drinking Water Public Laboratories Map and the PWS Laboratory Map Table found in the PWSSP webpage.

Reporting Coliform Sample Results

The Microbial Reporting Form (TCEQ Form 10525) is required when reporting coliform sample results to TCEQ for compliance with the RTCR and GWR only. Use of this form is mandatory unless the laboratory is submitting data electronically to TCEQ via Electronic Environmental Reporting System (E2). The MRF, with sample information, is included with the water samples sent to the laboratory for coliform analysis. The completed MRF, with the monthly coliform results must be submitted by the lab to TCEQ by the 10th day of the following month.

Electronic Reporting for Public Water Systems and Labs has information on the E2, a paperless reporting system that should be used by the lab that captures all the TCEQ required data. For users of the E2, the monthly coliform results must be submitted by the lab to TCEQ by the 10th day of the following month.

How to complete the MRF (Video 16 minutes) and Instructions for Completing the TCEQ Microbial Reporting Form for PWSs and Labs (TCEQ Form 10525/INST) provides guidance to the sample collector and labs about how the MRF must be completed. The lab will provide the MRF to the PWS.

When a positive coliform result is determined by the lab, they should immediately report the positive results to TCEQ and the PWS. The lab will use the Laboratory Positive Result Form – RTCR and GWR  (TCEQ Form 20894) to report each positive result to TCEQ. Labs should download the form to a computer and open using a non-web browser extension. The form may have limited functionality if opened in the web browser. Upon notification of a positive coliform result, the PWS must collect the repeat samples as outlined in their SSP within 24 hours of notification. The RTCR Positive Invalidation Request (TCEQ Form 20629) contains guidance and requirements regarding coliform data invalidations.

Seasonal Public Water Systems

Seasonal PWSs are transient non-community water systems that do not operate for the entire year and start up and shut down at the beginning and end of each operating season. To ensure the water meets TCEQ drinking water standards and the facilities are in good working order every seasonal system must complete the Seasonal System Start-up Procedures Checklist and Certification Form (TCEQ Form 20892). These procedures must be completed during the month prior to the beginning of the operating season and the form must be submitted to TCEQ prior to the system actively serving customers.

Level 1 and Level 2 Assessments

The Level 1 and Level 2 Assessment are an evaluation of your public water system to identify potential or actual causes of microbial contamination, also called a sanitary defect. If a sanitary defect is identified during an assessment, it should be corrected as soon as possible to protect public health.

If your PWS is required to complete an assessment it is not a violation and does not require a public notice. You must evaluate your PWS by answering the questions in the assessment form and providing the required documentation. The PWS has 30 days from the date of triggering the assessment to complete the assessment and provide the documentation to TCEQ.

An assessment will be required when:

  • A PWS collecting 40 or more routine coliform samples per month exceeds 5.0% total coliform positive samples in one month.
  • A PWS collecting less than 40 routine coliform samples per month has two or more total coliform positive samples in one month.
  • A PWS does not collect every required repeat sample.
  • An E. coli MCL violation occurs.

Level 1 Assessment Form                     Level 1 Assessment Form (TCEQ Form 20901)

Level 2 Assessment Form                     Level 2 Assessment Form (TCEQ Form 20769)

Public Notice Requirements

All public notices for the RTCR violations, including the acute E. coli maximum contaminant level violation, can be found at Public Notice Language for Drinking Water Compliance, under Microbial Violations.

2020 Public Drinking Water Conference RTCR Presentations

Common RTCR Assessment Findings Presentation reviews the purpose of the Level 1 Assessment Form, assessment triggers, common issues, sanitary defects, and corrective actions.

RTCR Data Reporting Presentation explains compliance with the RTCR routine distribution sample requirements, how to collect, submit, and report samples to the TCEQ and PWS and laboratory roles in maintaining data integrity in this process.

Sampling, Recording Keeping, and Contingency Planning for RTCR Presentation covers the Quality Assurance Project Plan and how it impacts RTCR, proper coliform sampling procedures, required elements of a Sample Siting Plan (SSP), how to properly complete the Microbial Reporting Form, record retention required under the RTCR program, and contingency planning for RTCR.

Sample Siting Plans and Coliform Sample Collection Presentation covers the requirements of the Sample Siting Plan, coliform sample site selection, sample collection, the Microbial Reporting Form, and proper documentation of distribution coliform samples.

Assistance and Helpful Links

TCEQ's Drinking Water Watch holds the information we have for your public water system and is open to the public. This has contact information, sample sites, sample results, violations, and public notice due dates.

TCEQ's Groundwater Rule provides increased public health protection against microbial pathogens at groundwater sources.

TCEQ's Financial, Managerial, and Technical (FMT) Assistance program offers free financial, managerial, and technical assistance to help public water and wastewater systems comply with regulations.

TCEQ's Public Notice Language for Drinking Water Compliance