We've made some changes to EPA.gov. If the information you are looking for is not here, you may be able to find it on the EPA Web Archive or the January 19, 2017 Web Snapshot.

EPA's website will operate in a diminished capacity on Saturday Feb 17, 2018 from 8:00 a.m. to noon EST for routine maintenance. Some services, such as search, may be temporarily unavailable for brief periods during this time. We apologize for any inconvenience.

Certification of Laboratories for Drinking Water

Supplement 2 to the Fifth Edition of the Manual for the Certification of Laboratories Analyzing Drinking Water

The Long Term 2 Enhanced Surface Water Treatment Rule (LT2 Rule) (40 CFR 9, 141, 142) requires public water systems that use surface water or ground water under the direct influence of surface water to monitor their source water (influent prior to treatment) for Cryptosporidium and E. coli and turbidity (40 CFR 141.701).

You may need Adobe Reader to view files on this page. See EPA’s About PDF page to learn more.