To use the IDEXX Colilert-18 for Fecal Coliforms:

The U.S. EPA Region 10 will accept Alternate Testing Procedure (ATP) applications from individual laboratory facilities and will authorize its use on a case by case basis. Laboratories should obtain their ATP approval and submit a copy of the approval letter when they first submit Fecal Coliform results using Colilert-18.

• EPA Microbiological Alternate Test Procedure (ATP) Protocol for Drinking Water, Ambient Water, Wastewater, and Sewage Sludge Monitoring Methods (pdf)
• EPA Office of Water CWA ATP Application Completeness Checklist (pdf)
• Colilert-18 Fecal Coliform Protocol Addendum (pdf)