External Guidance for Treatment and Monitoring of Pathogens at Public Water Systems
Find guidance for surface water and groundwater requirements to treat and monitor pathogens at public water systems.
Meeting Treatment Technique Requirements for Cryptosporidium, Giardia, and Viruses / PDF 
This external guidance document provides public water systems with information on pathogen-removal criteria when using Reverse Osmosis (RO) membranes to treat surface water, groundwater under the influence of surface water, or rain water.

This external guidance document provides public water systems with information on pathogen-removal criteria when using Reverse Osmosis (RO) membranes to treat surface water, groundwater under the influence of surface water, or rain water.