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Water Distribution SystemsIntermediate 12 min read

Illinois Distribution Operations & the Lead Service Line Replacement Mandate

Illinois distribution operators face the nation's largest lead service line inventory and a hard state-law deadline to map and replace it — here's the regulatory framework and what it means day to day.

Illinois Distribution Operations & Lead Service Lines
The Scale of the Problem
Illinois — and Chicago specifically — has more documented lead service lines than any other city in the United States. Illinois EPA counts approximately 667,275 known lead service lines statewide, plus over 1,000,000 additional lines of galvanized steel or unknown material that may also require replacement. This is a direct legacy of Chicago's historical plumbing code, which mandated lead service lines longer than most other major U.S. cities.
The Lead Service Line Replacement and Notification Act
Signed into law in 2021 as Public Act 102-0613 (effective January 1, 2022), this Act requires every community water supply in Illinois to:
  1. Develop a comprehensive service line material inventory covering both the utility-owned and privately-owned portions of each service line.
  2. Develop a

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