Revised Total Coliform Rule

The Revised Total Coliform Rule (RTCR) replaced the Total Coliform Rule on April 1, 2016. It requires systems vulnerable to contamination to find and fix problems and pathways that could allow pathogens to enter the distribution system.

We have always required water systems to look for maintenance or operational defects that could allow contamination to enter a system. RTCR formalizes the process. It requires water systems to assess their entire system—from sample collection point to source of supply—and submit an assessment report to us within 30 days after specific “trigger” events occur.

Level 1 assessment: Triggered by lower-risk events. A basic evaluation anyone familiar with the water system can do.

Level 2 assessment: Triggered by confirmed E. coli or repeated total coliform contamination. A detailed evaluation only a person with state-required qualifications can do.

Preventing contamination is the best strategy for protecting public health. You can quickly assess and take corrective action by:

  • Conducting routine surveillance of your facilities.
  • Using standard operating procedures and keeping them current.
  • Learning the scope of both assessments and knowing when you must use them.

Key provisions:

  • Begins April 1, 2016, for all systems.
  • Maintains the coliform monitoring schedule on your Water Facilities Inventory form.
  • Requires assessments and corrective actions.
  • Changes the Acute Maximum Contaminant Level (MCL) to E. coli MCL; removes Non-Acute MCL.
  • Requires updating or revising coliform monitoring plans.
  • Changes monitoring, reporting, and public notification requirements.
  • Requires start-up procedures for seasonal systems.

For more information:

Contact us

Northwest Regional Office, Kent
Coliform Program: 253-395-6775 Main Office: 253-395-6750

Southwest Regional Office, Tumwater
Coliform Program: 360-236-3045 Main Office: 360-236-3030

Eastern Regional Office, Spokane
Coliform Program: 509-329-2134 Main Office: 509-329-2100