Washington Grease Trap Regulations (2026)
Everything a Washington restaurant or commercial kitchen needs to know about grease trap requirements: who regulates it, how often you must clean, what permits and registration you need, 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.
Washington Requirements at a Glance
| Cleaning frequency | No statewide interval — set by local sewer utilities. Seattle requires cleaning when 25% of interceptor volume is grease and food waste (typically every 1–3 months); Tacoma requires monthly service on standard interceptors. |
| State regulator | Washington State Department of Ecology, Water Quality Program |
| Governing regulation | WAC 173-308 (Biosolids Management, governs grease trap waste transport/disposal); RCW 90.48 (Water Pollution Control) for enforcement authority |
| Manifest required | Yes — waste tracking form (manifest) for every load discharged under WAC 173-308 (source) |
| Licensed hauler required | Yes — Septage/biosolids haulers operate under WAC 173-308 with authorization from the local health jurisdiction or Ecology; King County runs its own on-site sewage professional certification for pumpers (source) |
| Record retention | at least 3 years in Seattle — cleaning dates, service provider, and disposal documentation (SMC 21.16.310) (source) |
| Penalties | Seattle civil penalties run $250–$5,000 per violation (SMC 21.16.310), plus cost-recovery for any sewer damage. State enforcement under RCW 90.48 allows additional civil and criminal penalties. (source) |
Who Regulates Grease Traps in Washington
At the state level, Washington State Department of Ecology, Water Quality Program (program page) oversees FOG (fats, oils, and grease) discharge; the governing rule is WAC 173-308 (Biosolids Management, governs grease trap waste transport/disposal); RCW 90.48 (Water Pollution Control) for enforcement authority. 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
Washington requires grease trap waste to be transported by licensed/registered haulers under Septage/biosolids haulers operate under WAC 173-308 with authorization from the local health jurisdiction or Ecology; King County runs its own on-site sewage professional certification for pumpers. (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 (waste tracking form (manifest) for every load discharged under WAC 173-308) at every service — date, volume removed, hauler license, disposal facility. (source)
- Keep records at least 3 years in Seattle — cleaning dates, service provider, and disposal documentation (SMC 21.16.310). (source)
- Track everything in one place: free maintenance log and cleaning schedule template.
City Programs in Washington
Cities run their own FOG programs and often set stricter rules than the state:
Seattle
- Program: Seattle Public Utilities FOG Program — mandatory grease interceptor install and maintenance for all food businesses with a King County Food Business Permit
- Ordinance: Seattle Municipal Code §21.16.300 and §21.16.310
- Cleaning frequency: Clean when 25% of interceptor volume is grease and food waste — typically every 1–3 months
- Permit: Interceptor install plans must be approved; enzyme/emulsifier/bio-additives are prohibited
- Fines: $250–$5,000 per violation plus sewer-damage cost recovery
Tacoma
- Program: City of Tacoma Environmental Services FOG Management Program (also covers Fife, Fircrest, Ruston, and parts of Pierce County)
- Ordinance: Tacoma Ordinance 29015; FOG Management Policy (January 2025)
- Cleaning frequency: Standard interceptors: monthly or as needed; self-cleaning hydromechanical units: licensed pumper every 3 months
- Permit: Register with Environmental Services and submit maintenance reports electronically within 7 days of each cleaning
Worth Knowing in Washington
Washington sets no statewide cleaning mandate — local utilities implement the federal pretreatment framework (40 CFR Part 403). Seattle explicitly bans enzymes, emulsifiers, and bio-additives in grease interceptors, so the 'pour-a-treatment-in' shortcut some vendors sell is actually a violation there. Tacoma's program was refreshed in January 2025 under Ordinance 29015.
Frequently Asked Questions
How often must grease traps be cleaned in Washington?
No statewide interval — set by local sewer utilities. Seattle requires cleaning when 25% of interceptor volume is grease and food waste (typically every 1–3 months); Tacoma requires monthly service on standard interceptors. 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 Washington?
Yes. Get a signed manifest (waste tracking form (manifest) for every load discharged under WAC 173-308) from the hauler at every service and keep it at least 3 years in Seattle — cleaning dates, service provider, and disposal documentation (SMC 21.16.310). It's the document inspectors ask for first.
What are the penalties for grease trap violations in Washington?
Seattle civil penalties run $250–$5,000 per violation (SMC 21.16.310), plus cost-recovery for any sewer damage. State enforcement under RCW 90.48 allows additional civil and criminal penalties. 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 Washington?
No — use a licensed/registered hauler (Septage/biosolids haulers operate under WAC 173-308 with authorization from the local health jurisdiction or Ecology; King County runs its own on-site sewage professional certification for pumpers). If your hauler dumps illegally, the paper trail you kept is your protection. Verify registration on the official lookup linked above.
Do I need a permit for a grease trap in Washington?
In most Washington cities, yes — food service establishments must register with, or get a permit from, the local FOG / pretreatment program before discharging grease trap waste to the sewer. The exact permit and registration requirements vary by city; the major-city programs are listed above, and your local sewer authority has the specifics for your address.
Next Steps
- Find grease trap cleaning companies in Washington
- Run the Washington-adapted compliance checklist
- Put manifests and pricing in writing (free template)
Official Sources
- https://app.leg.wa.gov/wac/default.aspx?cite=173-308&full=true
- https://www.seattle.gov/utilities/protecting-our-environment/sustainability-tips/fats-oils-and-grease-(fog)/fog-commercial-kitchens
- https://kingcounty.gov/en/dept/dph/health-safety/environmental-health/on-site-sewage-systems/resources-for-sewage-septic-professionals/certifications
- https://www.cityoftacoma.org/in_the_news/tacoma_city_council_adopts_ordinance_29015_to_help_food_and_beverage_businesses_navigate_grease_interceptor_requirements
This guide summarizes official sources for general information and is not legal advice. Rules change — confirm requirements with Washington State Department of Ecology, Water Quality Program and your local FOG program.
Washington Grease Trap Costs & Rules by City
City-level pricing, cleaning frequency and permit requirements:
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