EPA Region 8 Drinking Water Unit Tech Tips for WY & Tribal Systems: Follow-up to a Total Coliform Positive (TC+) or E. Coli (EC+) Sample
When a water system receives a total coliform positive or total coliform present sample result, within 24 hours, the owner or operator of the system must collect a set of repeat total coliform samples in the distribution system for the Revised Total Coliform Rule (RTCR); additionally, all groundwater sources must be sampled for E. coli under the Ground Water Rule (GWR).