{"data":{"id":"us/40-cfr-121.10","jurisdiction":"us","citation":"40 CFR 121.10","heading":"Modification to a grant of certification.","body":"(a) Provided that the Federal agency and the certifying authority agree in writing that the certifying authority may modify a grant of certification (with or without conditions), the certifying authority may modify only the agreed-upon portions of the certification. The certifying authority is not required to obtain the Federal agency's agreement on the language of the modification.\n(b) The certifying authority shall not, through a modification pursuant to paragraph (a) of this section:\n(1) Revoke a grant of certification (with or without conditions); or\n(2) Change a grant of certification (with or without conditions) into a denial or waiver of certification.","path":["Title 40—Protection of Environment","CHAPTER I—ENVIRONMENTAL PROTECTION AGENCY","SUBCHAPTER D—WATER PROGRAMS","PART 121—STATE CERTIFICATION OF ACTIVITIES REQUIRING A FEDERAL LICENSE OR PERMIT","Subpart A—General"],"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":"a2fc0096d4dafd4e4b220179a26cbc64467e5b0eaa975eb9745f77675877ded4","source_id":"us-cfr","stale":true,"prev":"us/40-cfr-121.9","next":"us/40-cfr-121.11"},"notice":"GroundRules: Original legal text. Not legal advice."}