REGULATIONS State-specific

Illinois Plumbing Code & Permit Rules

Illinois Plumbing Code (IPC-based with heavy amendments) (2014)

Data sources: State plumbing boards, ICC, IAPMO, EPA Last verified: 2026-03-16

State-specific
Plumbing Code
Required
Annual Backflow Test
No
Homeowner DIY
Yes
Water Heater Permit

Plumbing Code

Illinois follows the Illinois Plumbing Code (IPC-based with heavy amendments) (2014 edition).

Based on IPC but heavily amended; not a straight IPC adoption

Illinois maintains its own plumbing code rather than adopting IPC or UPC directly. Contact your local building department for specific requirements.

Backflow Prevention Testing

Annual testing is required in Illinois for testable backflow prevention assemblies (RPZ, DCVA, PVB).

  • Residential: Yes — required for homes with irrigation systems or other cross-connections
  • Who can test: Licensed plumber
  • Enforcement: IEPA; local water utilities
  • Note: Statewide mandate; covers irrigation and commercial

Water Heater Installation

A permit is required to replace or install a water heater in Illinois.

  • Licensed plumber required: Yes
  • Homeowner can DIY: No — licensed plumber required
  • Note: Licensed plumber required for all plumbing work

Universal requirements (all states):

  • Temperature & Pressure Relief (TPR) valve must be installed
  • Discharge pipe from TPR must terminate safely
  • Gas water heaters: proper venting required
  • Minimum 18" clearance from floor for gas heaters in garages
  • Expansion tank often required when backflow preventer is installed on main supply

Homeowner DIY Plumbing Rights

Illinois requires a licensed plumber for plumbing work. Homeowner DIY is generally not permitted.

Licensed plumber required for all plumbing work

Water Conservation Requirements

Illinois follows federal water conservation minimums (no additional state mandates).

Federal minimums apply

Lead Service Line Replacement

Under the revised EPA Lead and Copper Rule (2021), Illinois is required to inventory lead service lines and develop replacement plans.

Massive lead service line replacement program (Chicago); aggressive state mandate

Important Disclaimer

This information is provided as a general overview. Plumbing codes and regulations can vary significantly between municipalities within Illinois. Always check with your local building department before starting any plumbing work. Local codes override state minimums — your city or county may have stricter requirements.

Sources

  • State plumbing boards and licensing agencies
  • International Code Council (ICC) — IPC adoption map
  • International Association of Plumbing and Mechanical Officials (IAPMO) — UPC adoption
  • EPA Safe Drinking Water Act — Cross-Connection Control Program
  • State building departments
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