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Revised Total Coliform Rule for Drinking Water

The federal Safe Drinking Water Act (SDWA) requires that all public water systems provide an adequate supply of safe drinking water to their customers and consumers. IDEM’s Drinking Water Branch is responsible for implementing and managing the SDWA at the state level.

On April 1, 2016, the Revised Total Coliform Rule (RTCR) became effective, replacing the Total Coliform Rule. The RTCR establishes a maximum contaminant level (MCL) for E. coli, an indicator of fecal contamination. The RTCR prompts public water systems that are vulnerable to contamination to find and fix problems. The RTCR aims to improve public health protection by reducing the pathways through which fecal contamination and pathogens can enter the water system.

Owners and operators will be taking on a more active role in assessing their water system for possible deficiencies, when triggered by a coliform positive sample. For non-community systems, failure to maintain compliance under the RTCR may increase sampling from quarterly to monthly monitoring. Once increased, a return to quarterly monitoring will remain an option; however, additional steps are required, including an inspection.

The Drinking Water Branch is working with all systems regarding the changes and their responsibilities under the RTCR. To aid this effort, this website has been developed to better educate all systems of their new requirements.

Referenced forms are available on the IDEM Agency Forms page.

How can systems learn more about RTCR and its many new requirements?

The following presentations are instructional & training guides for water system owners and drinking water operators. Important note – some of these presentations have audio included that expand upon the information found in the slides. Please make sure your volume is turned up or you have headphones connected, so that you may hear the audio instructions as well. Advance the slides using the controls at the bottom. Captioning is available on the presentations.

  • Intro:
    • This presentation is an introduction to the Revised Total Coliform Rule (RTCR)
  • Seasonal Systems:
    • This lesson focuses on the RTCR and how it applies to Seasonal Systems.
  • Level 1 Assessment:
    • This presentation concentrates on the Level 1 assessment portion of the RTCR.
  • Level 2 Assessment:
    • This presentation explains the Level 2 assessment portion of the RTCR.
  • Violations and Public Notice:
    • This session details violations and public notices in regards to the RTCR.
  • TCR vs. RTCR:
    • This lesson depicts the differences between the RTCR vs. the old Total Coliform Rule.

What do systems need to do?

Site Sampling Plans are a key part of the RTCR Rule. Each water system needs to develop a site sampling plan and have it approved by IDEM to be in compliance with this rule. Site Sampling Plan templates are available for each type of water system (transient, non-transient non-community, and community). Please make sure the appropriate template is used.

What’s new for Seasonal Systems?

Seasonal water systems must follow new start-up requirements to help keep drinking water safe. IDEM’s DWB has developed a check list to help all seasonal systems complete the proper start-up procedures. RTCR also requires seasonal systems to collect monthly samples for total coliform, and have them tested, during the months they are in operation.

  • Seasonal Systems Start-Up Requirements
  • Seasonal Systems with Hand Pump(s) Only, Start-Up Requirements

What are assessments?

An assessment is a review of a system’s infrastructure and operating practices to identify potential pathways for contamination. Assessments are required after a system has exceeded certain Treatment Technique (TT) triggers.

The following form documents provide more information on assessments:

  • Level 1 Assessment Transient Non-Community Water Systems
  • Level 1 Assessment Non-Transient Non-Community (NTNC) or Community Water Systems (CWS)
  • Level 2 Assessment Transient Non-Community Water Systems
  • Level 2 Assessment Non-Transient Non-Community (NTNC) or Community Water Systems (CWS)

Want to know more information about RTCR?

These reference guides provide information to help drinking water operators gain a better understanding of this new rule and how it serves to help keep water systems safe and in compliance. These guides also have important contact information for IDEM's Drinking Water Branch staff.

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