Data sources: State plumbing boards, ICC, IAPMO, EPA Last verified: 2026-03-17

Plumbing Code

Illinois follows the Illinois Plumbing Code (2014 edition).

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: May be required for homes with irrigation systems or other cross-connections; check local water-supplier rules
• 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
• Gas water heaters in garages: an 18" elevation of the ignition source above the floor may apply, subject to equipment exceptions and local code
• Expansion tank often required when backflow preventer is installed on main supply

Homeowner DIY Plumbing Rights

Illinois requires a licensed plumber for plumbing work. Check whether a homeowner exemption applies to plumbing on your own residence; permits and inspections are usually still required.

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 EPA Lead and Copper Rule Revisions (2021), water systems in Illinois must inventory service lines; the Lead and Copper Rule Improvements (2024) add requirements to replace lead service lines. Ask your water system for its inventory and replacement plan.

Lead service line replacement program (Chicago); check current program details with your utility

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
• Manual de control de conexiones cruzadas de la EPA (guía de la Ley de Agua Potable Segura)
• State building departments

Sources

• Illinois state plumbing board and licensing agency
• International Code Council (ICC) - IPC adoption map
• International Association of Plumbing and Mechanical Officials (IAPMO) - UPC adoption
• EPA Cross-Connection Control Manual (Safe Drinking Water Act guidance)
• State and local building departments