StacksVerified U.S. regulatory reference

40 CFR §141.535

Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗
If your system uses chloramines, ozone, or chlorine dioxide for primary disinfection, you must also calculate the logs of inactivation for viruses and develop an additional disinfection profile for viruses using methods approved by the State.