An official website of the United States government.

This is not the current EPA website. To navigate to the current EPA website, please go to This website is historical material reflecting the EPA website as it existed on January 19, 2021. This website is no longer updated and links to external websites and some internal pages may not work. More information »

Drinking Water Requirements for States and Public Water Systems

Turbidity Provisions

These guidance documents support the Surface Water Treatment Rules and the treatment requirements for public water systems complying with those rules. These documents provide guidance for public water systems that need to consider changes to their treatment processes to ensure compliance with requirements of the suite of Surface Water Treatment Rules including the Long Term 2 Enhanced Surface Water Treatment Rule and Stage 2 Disinfectants and Disinfection Byproducts Rule.

You may need a PDF reader to view some of the files on this page. See EPA’s About PDF page to learn more.
  • Turbidity Provisions (PDF)(144 pp, 3 MB, July 2020, 815-R-20-004)
    EPA provides guidance documents to help states and public water systems (PWSs) implement the Stage 1 and Stage 2 Disinfectants and Disinfection Byproducts (DBP) Rules. The materials below can assist in complying with requirements of these Rules including updates to reflect the Stage 2 DBP Rule.