{"data":{"id":"us/40-cfr-141.536","jurisdiction":"us","citation":"40 CFR 141.536","heading":"My system has developed an inactivation ratio; what must we do now?","body":"Each log inactivation serves as a data point in your disinfection profile. Your system will have obtained 52 measurements (one for every week of the year). This will allow your system and the State the opportunity to evaluate how microbial inactivation varied over the course of the year by looking at all 52 measurements (your Disinfection Profile). Your system must retain the Disinfection Profile data in graphic form, such as a spreadsheet, which must be available for review by the State as part of a sanitary survey. Your system must use this data to calculate a benchmark if you are considering changes to disinfection practices.","path":["Title 40—Protection of Environment","CHAPTER I—ENVIRONMENTAL PROTECTION AGENCY","SUBCHAPTER D—WATER PROGRAMS","PART 141—NATIONAL PRIMARY DRINKING WATER REGULATIONS","Subpart T—Enhanced Filtration and Disinfection—Systems Serving Fewer Than 10,000 People"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-40.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:26:04Z","sha256":"9052c6733c7d78b0de88f987ccdd7b37dc116a373a2a78f7ade9f92fc1491c73","source_id":"us-cfr","stale":true,"prev":"us/40-cfr-141.535","next":"us/40-cfr-141.540"},"notice":"GroundRules: Original legal text. Not legal advice."}