What are the grease trap requirements in Milwaukee, WI?

Food service establishments in Milwaukee must install and maintain grease traps or interceptors per local FOG ordinances. The city follows the Uniform Plumbing Code (UPC).

What size grease trap do I need for my restaurant in Milwaukee?

Grease trap sizing depends on your establishment's flow rate, number of fixtures, and local code requirements. 750 gallons minimum for gravity grease interceptors; hydromechanical units sized per Wisconsin Plumbing Code SPS 382 fixture unit tables (minimum 20 GPM). Use our free sizing calculator for a recommendation.

Grease Trap Requirements
Milwaukee, WI

Q: Do I need a grease trap permit in Milwaukee?

Yes, a FOG permit is required in Milwaukee. Fee: No separate published annual FOG permit fee; plumbing permit required for interceptor installation; MMSD sewer use charges apply.

FOG compliance regulations for food service establishments in Milwaukee, Wisconsin. Serving 2,122 food service establishments.

Every 90 days minimum

Pumping Freq.

Required

Permit

Yes

25% Rule

UPC

Code Base

Pumping Requirements

Frequency Every 90 days minimum; interceptors must be cleaned before FOG and solids accumulation exceeds 25% of capacity

25% Rule Applies

Permits & Enforcement

Permit Required Required

Permit Fee No separate published annual FOG permit fee; plumbing permit required for interceptor installation; MMSD sewer use charges apply

Max Fine $5,000 per violation per day under city sewer use ordinance; MMSD may assess surcharges for non-compliance

Complete FOG Regulations

Minimum Trap Size	750 gallons minimum for gravity grease interceptors; hydromechanical units sized per Wisconsin Plumbing Code SPS 382 fixture unit tables (minimum 20 GPM)
Pumping Frequency	Every 90 days minimum; interceptors must be cleaned before FOG and solids accumulation exceeds 25% of capacity
25% Rule	Yes — trap must be pumped when grease and solids reach 25% of capacity
Permit Required	Yes
Permit Fee	No separate published annual FOG permit fee; plumbing permit required for interceptor installation; MMSD sewer use charges apply
Maximum Fine	$5,000 per violation per day under city sewer use ordinance; MMSD may assess surcharges for non-compliance
Inspections	Annual inspections by MMSD or city inspectors; complaint-driven inspections also conducted
Record Keeping	Required — maintain pumping logs and manifests on-site
Plumbing Code	Uniform Plumbing Code (UPC)
Ordinance Ref.	Milwaukee Code of Ordinances Chapter 225 - Sewers; Wisconsin Plumbing Code SPS 382.34 - Interceptors; MMSD Chapter 11 Sewer Use Rules
Authority	Milwaukee Metropolitan Sewerage District (MMSD); City of Milwaukee Department of Neighborhood Services (plumbing permits)

Additional Notes

Wisconsin has its own state plumbing code (SPS 382) which is historically based on UPC principles. Milwaukee FOG compliance is enforced jointly by the Milwaukee Metropolitan Sewerage District (MMSD) for sewer use and the city Department of Neighborhood Services for plumbing code compliance. All FSEs must install and maintain grease interceptors. MMSD has authority to require monitoring, impose surcharges, and take enforcement action for sewer blockages caused by FOG. Grease hauling records must be retained for at least 3 years.

Regulations change frequently. Always verify current requirements with your local wastewater authority or plumbing inspector before making compliance decisions. Last updated: March 2026.