US lawIllinoisRegulationsTitle 35 — ENVIRONMENTAL PROTECTIONCHAPTER I: POLLUTION CONTROL BOARDPart 611 — PRIMARY DRINKING WATER STANDARDSSubpart P611.68635 Ill. Adm. Code 611.686Modification to System (Repealed)Last amended: 2004Year: 2026Length: 8 wordsOfficial source Section 611 Section 611.686 Modification to System (Repealed)Previous35 Ill. Adm. Code 611.685Next35 Ill. Adm. Code 611.687