Illinois's Split Rule: Homeowner Piping, Licensed Plumber for Backflow
Illinois does not have a statewide irrigation contractor licensing program — unlike Texas or Florida. Instead, irrigation system regulation in Illinois falls under the state's plumbing licensing law (225 ILCS 320), which creates an important and often misunderstood split:
- Irrigation piping (polyethylene pipe, heads, valves, wiring, controller): Homeowners may generally install this themselves under the owner-builder provisions, with a local permit.
- Backflow prevention device installation: This is classified as plumbing work in Illinois. Only a licensed plumbing contractor may legally connect the backflow preventer to the potable water supply. A homeowner cannot legally install the backflow device themselves under Illinois state law, regardless of what any individual municipality says.
Even if your village or city building department doesn't specifically call out this requirement, it flows from 225 ILCS 320 — the Illinois Plumbing License Act. Any work involving a connection to a potable water supply line requires a licensed plumber. Installing the backflow device is that connection. This is the single most commonly misunderstood rule in Illinois irrigation permitting.
What This Means for Your Project Cost
The practical effect of this split rule is that most Illinois homeowners hire a plumber for the backflow device and do the rest themselves, or hire an irrigation contractor who subcontracts the backflow work to a licensed plumber. Here's how typical Illinois projects are structured:
- DIY-plus-plumber approach: Homeowner installs all irrigation pipe, heads, valve manifold, and controller. Licensed plumber installs and tests backflow device. Homeowner pulls the building permit; plumber pulls a separate plumbing permit for the backflow connection. Most cost-effective hybrid approach.
- Full irrigation contractor approach: Irrigation contractor handles the entire system. Licensed plumber on their team installs backflow. One permit pulled by the contractor. Simpler, higher cost.
- Homeowner-only (not recommended): Homeowner installs everything including backflow. Technically violates 225 ILCS 320. May pass inspection depending on the municipality, but creates liability risk and potential insurance issues.
Local Permit Requirements by Illinois Municipality
Because Illinois has no statewide irrigator licensing, permit requirements are set entirely at the local level. Here's what key Illinois municipalities require:
| Municipality | Permit Required | Backflow Type | Testing Frequency | Notes |
|---|---|---|---|---|
| Chicago | Yes | RPZ required | Annual | Chicago requires RPZ for all irrigation — not just chemical injection. Permit through Chicago Building Department. Licensed plumber required for all connections to water supply. Annual test results must be filed with CDWM. |
| Schaumburg | Yes | RPZ or PVB | Annual | Village of Schaumburg requires permit and inspection. RPZ required for any system with chemical injection; PVB accepted for standard systems. Backflow installer must be licensed plumber. |
| Naperville | Yes | RPZ or PVB | Annual | Naperville Public Utilities requires backflow device registration. Annual test results must be submitted by May 31 each year. Licensed plumber required for backflow installation. |
| Aurora | Yes | RPZ or PVB | Annual | City of Aurora Building Department issues irrigation permits. Backflow test required within 30 days of installation and annually thereafter. |
| Rockford | Yes | PVB minimum | Annual | Rockford Water follows IEPA cross-connection program. Annual test letters mailed to property owners. Failure to test can result in water service interruption. |
| Springfield | Yes | PVB or RPZ | Annual | City Water, Light and Power requires backflow device registration. Permit required from City Building and Zoning before installation. |
| Peoria | Yes | PVB minimum | Annual | City of Peoria Building Department. Cross-connection control program administered by Peoria Public Works. |
| Joliet | Yes | RPZ or PVB | Annual | Joliet City requires permit. IEPA cross-connection rules apply. Licensed plumber required for backflow device. |
Illinois Annual Backflow Testing: What You Need to Know
Annual backflow preventer testing is required by virtually every Illinois water utility under the Illinois Environmental Protection Agency (IEPA) cross-connection control program. Key points:
- Testing must be performed by a certified backflow assembly tester — not just any plumber
- Most Illinois utilities mail compliance notices in early spring (March–April) before irrigation season
- Test results must typically be submitted to your water utility within 30–60 days of receiving the notice
- Failure to test can result in water service termination — Illinois utilities have broad authority to shut off service for cross-connection compliance failures
- Cost of annual testing typically runs $50–$100 for a residential PVB; $75–$150 for an RPZ
To find a certified backflow tester in Illinois, contact your water utility — most maintain a list of approved testers. The Illinois Section of the American Water Works Association (ISAWWA) also maintains resources for cross-connection control.
How to Get an Irrigation Permit in Illinois
- Contact your local building department before starting. In Illinois, this is almost always the village or city building department — not the county.
- Determine permit type. You may need both a building permit (for the overall system) and a plumbing permit (for the backflow connection). Many municipalities issue both under one application; others require separate submissions.
- Hire a licensed plumber for the backflow device. Get this arranged early — it affects your project timeline.
- Submit application with site plan. Show the home footprint, irrigation zone layout, location of water connection, and backflow device location.
- Pay fees. Irrigation permits in Illinois typically cost $75–$200 depending on the municipality. Chicago is higher.
- Schedule inspection. After installation, schedule a final inspection. The backflow device must be operational and tested before the permit closes.
- Register backflow device with utility. Most Illinois utilities require registration of the backflow device within 30 days of installation. The licensed plumber who installed it often handles this — confirm they do.
Frequently Asked Questions — Illinois Irrigation Permits
You can install most of the system yourself — the pipe, heads, valve manifold, wiring, and controller — under an owner-builder permit in most Illinois municipalities. However, the backflow preventer must be installed by a licensed plumbing contractor under 225 ILCS 320. This is a statewide requirement that flows from the Illinois Plumbing License Act. Even if a local inspector doesn't ask about who installed the backflow device, the state law still applies.
No — Illinois does not have a statewide irrigation contractor license like Texas (TCEQ) or Florida (FDACS). Irrigation contractors in Illinois typically hold a plumbing contractor license, a general contractor license, or operate under the homeowner exemption. The key licensing requirement is specifically for plumbing work — including backflow device installation — which requires a licensed plumber.
Requirements vary by municipality and by system type. For standard residential irrigation connected to municipal water without chemical injection, a Pressure Vacuum Breaker (PVB) is commonly accepted. Chicago and some other municipalities require an RPZ (Reduced Pressure Zone) as their baseline standard. If your system includes a fertilizer or pesticide injector, an RPZ is required statewide. Check with your local water utility — they set the specific device type requirement, not just the building department.
Illinois municipalities handle unpermitted work differently, but the most common path is an after-the-fact permit (sometimes called a permit for existing work). You'll typically pay a double permit fee and the inspector may require you to expose piping or demonstrate proper backflow device installation. Most critically — if no backflow device was installed, you'll need to hire a licensed plumber to install one before the permit can close. Utilities can also require backflow device testing as part of their cross-connection program regardless of whether a permit was pulled.
Related: Backflow Preventer Types · Annual Backflow Testing · Homeowner Exemptions by State · Permit Checker Tool