{"data":{"id":"us/40-cfr-141.521","jurisdiction":"us","citation":"40 CFR 141.521","heading":"What updated watershed control requirements must my unfiltered system implement to continue to avoid filtration?","body":"Your system must take any additional steps necessary to minimize the potential for contamination by Cryptosporidium oocysts in the source water. Your system's watershed control program must, for Cryptosporidium:\n(a) Identify watershed characteristics and activities which may have an adverse effect on source water quality; and\n(b) Monitor the occurrence of activities which may have an adverse effect on source water quality.","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":"c0bed4599276aa0e69c80d64c5975fdf9a170b72231249058b6d8a681fced892","source_id":"us-cfr","stale":true,"prev":"us/40-cfr-141.520","next":"us/40-cfr-141.522"},"notice":"GroundRules: Original legal text. Not legal advice."}