Official sources checked August 29, 2026
Benton County, Washington septic permits and requirements
Permitting authority
Benton-Franklin Health District — On-Site Sewage Program
Environmental Health / sewage systems: 509-460-4205. Kennewick office: 7102 W. Okanogan Place, Kennewick, WA 99336.
Washington local-health-jurisdiction framework
Washington State Department of Health assigns property-level onsite sewage permitting and management to local health jurisdictions. County or district rules and procedures can be more specific than the statewide minimums.
Local health district permits systems under 3,500 gallons per day
Benton-Franklin Health District states that it is responsible for permitting onsite septic systems with design flows below 3,500 gallons per day and for overseeing design, installation, and inspection.
Final inspection before backfill
After installation and before the system is backfilled, the owner or installer must request the Health District final inspection. The district states that the system is approved for use after it passes that final inspection.
As-built records are retained
After approval, the Health District keeps the original as-built drawing in its records and provides a copy showing the final septic-system location. Property owners can request existing system records using an address or parcel number.
Official sources
- Washington State Department of Health — Onsite Sewage Systems
- Benton-Franklin Health District — On-Site Sewage
- Benton-Franklin Health District — Applications, Lists and Forms
- Benton-Franklin Health District — Sewage System Inspection
- Benton-Franklin Health District — Sewage System Records
SepticScope summarizes public-agency information for planning purposes. The permitting agency's current instructions control if they differ from this guide.