Wisconsin Grease Trap Regulations (2026)
Everything a Wisconsin restaurant or commercial kitchen needs to know about grease trap compliance: who regulates it, how often you must clean, what records to keep, and what violations actually cost. Citations link to the official source so you can verify every claim — and show your inspector you did.
Wisconsin Requirements at a Glance
| Cleaning frequency | Wisconsin is one of the few states with a codified statewide cap: grease interceptors must be maintained on a cycle not to exceed 90 days (or per manufacturer instructions), and cleaned often enough to prevent grease passing through (SPS 382.34). |
| State regulator | Wisconsin DNR (Septage Certification) + Dept. of Safety and Professional Services (Plumbing Code) |
| Governing regulation | Wis. Admin. Code SPS 382.34 (grease interceptor design/maintenance); Wis. Admin. Code ch. NR 113 (septage servicing/disposal); Wis. Stat. §145.12 (plumbing penalties) |
| Manifest required | Yes — daily log book / invoice records kept in each vehicle, plus annual disposal reports (Forms 3400-055 and 3400-052) filed with DNR by January 31 (source) |
| Licensed hauler required | Yes — Wisconsin DNR Septage Business License (NR 113) — a certified master operator must be Operator-in-Charge; fees $50/WI vehicle, $100/out-of-state vehicle (source) |
| Record retention | 5 years — servicing records kept on file and available for inspection (Wis. Admin. Code NR 113) (source) |
| Penalties | Plumbing-code violations (SPS 382) carry fines of $100–$500 per violation or up to 30 days imprisonment under Wis. Stat. §145.12, with each day a separate offense; administrative forfeitures of $10–$1,000 per violation per day may also apply. (source) |
Who Regulates Grease Traps in Wisconsin
At the state level, Wisconsin DNR (Septage Certification) + Dept. of Safety and Professional Services (Plumbing Code) (program page) oversees FOG (fats, oils, and grease) discharge; the governing rule is Wis. Admin. Code SPS 382.34 (grease interceptor design/maintenance); Wis. Admin. Code ch. NR 113 (septage servicing/disposal); Wis. Stat. §145.12 (plumbing penalties). Day-to-day enforcement — inspections, cleaning intervals, fines — usually happens through your city or county sewer utility's pretreatment program, which can set stricter rules than the state.
Hauler Licensing & Verification
Wisconsin requires grease trap waste to be transported by licensed/registered haulers under Wisconsin DNR Septage Business License (NR 113) — a certified master operator must be Operator-in-Charge; fees $50/WI vehicle, $100/out-of-state vehicle. (source) Before signing a contract, verify the hauler's registration on the official lookup — it takes two minutes and it's the single best protection against illegal-dumping liability landing on you.
Manifests & Record Keeping
- Collect a signed manifest (daily log book / invoice records kept in each vehicle, plus annual disposal reports (Forms 3400-055 and 3400-052) filed with DNR by January 31) at every service — date, volume removed, hauler license, disposal facility. (source)
- Keep records 5 years — servicing records kept on file and available for inspection (Wis. Admin. Code NR 113). (source)
- Track everything in one place: free maintenance log and cleaning schedule template.
City Programs in Wisconsin
Cities run their own FOG programs and often set stricter rules than the state:
Milwaukee (MMSD)
- Program: Milwaukee Metropolitan Sewerage District Industrial Waste & Pretreatment Program
- Ordinance: MMSD Rules, Chapter 11 (Discharge Regulations)
- Cleaning frequency: State 90-day maximum (SPS 382.34) applies; MMSD may require more frequent service based on load
- Permit: Industrial wastewater discharge compliance required
Madison
- Program: City of Madison Engineering — Sanitary Sewer FOG Program
- Ordinance: Madison General Ordinances ch. 35
- Cleaning frequency: Maintenance performed and reported annually (by April 1); state 90-day maximum also applies
- Permit: Annual online grease trap maintenance report through the city permitting portal
- Fines: Non-compliance moves billing to a Tier 3 sanitary sewer rate (usage charge + 120%) until compliance is restored
Worth Knowing in Wisconsin
Wisconsin actually codifies a statewide maximum cleaning cycle — 90 days — in its plumbing code (SPS 382.34), which many states leave entirely to local rule. It also runs a dual system: DNR licenses septage/grease haulers under NR 113 while DSPS enforces the plumbing code. Madison is notable for enforcing with money rather than fines — miss your annual maintenance report and your sewer bill jumps to a Tier 3 rate (a 120% surcharge).
Frequently Asked Questions
How often must grease traps be cleaned in Wisconsin?
Wisconsin is one of the few states with a codified statewide cap: grease interceptors must be maintained on a cycle not to exceed 90 days (or per manufacturer instructions), and cleaned often enough to prevent grease passing through (SPS 382.34). Your city's FOG program may require more frequent service — and regardless of the legal interval, clean before fats, oils, and grease reach 25% of trap capacity.
Do I need a manifest for grease trap cleaning in Wisconsin?
Yes. Get a signed manifest (daily log book / invoice records kept in each vehicle, plus annual disposal reports (Forms 3400-055 and 3400-052) filed with DNR by January 31) from the hauler at every service and keep it 5 years — servicing records kept on file and available for inspection (Wis. Admin. Code NR 113). It's the document inspectors ask for first.
What are the penalties for grease trap violations in Wisconsin?
Plumbing-code violations (SPS 382) carry fines of $100–$500 per violation or up to 30 days imprisonment under Wis. Stat. §145.12, with each day a separate offense; administrative forfeitures of $10–$1,000 per violation per day may also apply. Enforcement is usually municipal, so your city's fine schedule controls — the fastest way to stay off it is a maintained cleaning schedule and complete records.
Can anyone pump my grease trap in Wisconsin?
No — use a licensed/registered hauler (Wisconsin DNR Septage Business License (NR 113) — a certified master operator must be Operator-in-Charge; fees $50/WI vehicle, $100/out-of-state vehicle). If your hauler dumps illegally, the paper trail you kept is your protection. Verify registration on the official lookup linked above.
Next Steps
- Find grease trap cleaning companies in Wisconsin
- Run the Wisconsin-adapted compliance checklist
- Put manifests and pricing in writing (free template)
Official Sources
- https://docs.legis.wisconsin.gov/code/admin_code/sps/safety_and_buildings_and_environment/380_387/382/III/34
- https://dnr.wisconsin.gov/topic/opcert/septageBusiness.html
- https://docs.legis.wisconsin.gov/statutes/statutes/145/12
- https://www.cityofmadison.com/engineering/sanitary-sewer/education/fats-oils-grease
- https://www.mmsd.com/government-business/rules-regulations/industrial-waste-pretreatment
This guide summarizes official sources for general information and is not legal advice. Rules change — confirm requirements with Wisconsin DNR (Septage Certification) + Dept. of Safety and Professional Services (Plumbing Code) and your local FOG program.
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