Wisconsin Grease Trap Regulations
FOG Compliance Overview
Wisconsin follows the Uniform Plumbing Code (UPC) as its base plumbing code. The UPC requires grease interceptors for commercial kitchens and uses fixture unit calculations for sizing requirements. The state's regulatory authority is the Wisconsin Department of Natural Resources (DNR).
With approximately 13,939 food service establishments statewide, Wisconsin has significant FOG compliance needs. Individual cities and municipalities may adopt additional local ordinances that go beyond the state plumbing code, including stricter pumping schedules, permit requirements, and enforcement penalties. Of the 4 cities we cover, 2 require a dedicated FOG permit. 3 cities enforce the 25% rule for grease trap pumping.
Need a grease trap in Wisconsin?
Our free calculator uses UPC code requirements to recommend the right size for your establishment.
Size My Grease TrapCity Regulations in Wisconsin
| City | Pumping Frequency | Permit | 25% Rule |
|---|---|---|---|
| Beloit | Must be pumped when grease and solids reach 25% of inte... | — | Yes |
| Madison | Regular pumping required; annual proof of maintenance m... | Required | Yes |
| Milwaukee | Every 90 days minimum; interceptors must be cleaned bef... | Required | Yes |
| Racine | See details | — | — |
Frequently Asked Questions
What plumbing code does Wisconsin follow for grease traps?
Wisconsin follows the Uniform Plumbing Code (UPC). The UPC requires grease interceptors for commercial kitchens and uses fixture unit calculations for sizing. Individual cities may adopt stricter local ordinances.
How many food service establishments are in Wisconsin?
Wisconsin has approximately 13,939 food service establishments according to Census Bureau County Business Patterns data. We currently cover detailed FOG regulations for 4 cities in the state.
Do I need a grease trap permit in Wisconsin?
Permit requirements vary by city. Of the 4 cities we cover in Wisconsin, 2 require a dedicated FOG permit. Check your specific city's requirements below or contact your local wastewater authority.
What size grease trap do I need in Wisconsin?
Grease trap sizing in Wisconsin depends on your establishment's flow rate, number of fixtures, and local code requirements under the UPC. Use our free sizing calculator for a recommendation tailored to your setup.
Regulations change frequently. Always verify current requirements with your local wastewater authority or plumbing inspector before making compliance decisions. Last updated: March 2026.