Washington Grease Trap Regulations (2026)
Everything a Washington 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.
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.
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.
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