Yakima County, Washington septic permits and requirements

Permitting authority

Yakima Health District — On-Site Sewage System Program

Environmental Health Help Desk: 509-249-6508; [email protected]; 1210 Ahtanum Ridge Drive, Union Gap, WA 98903.

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.

Check sewer availability first

Yakima Health District instructs applicants to confirm whether septic is allowed before beginning a new-system design. If public sewer is available within applicable service conditions, connection to sewer can be required instead of a new septic system.

Site and soil evaluation starts the new-system process

For a new system, the county directs applicants to submit an onsite sewage application for a site and soil evaluation and prepare test holes in the proposed drainfield area. The Health District evaluates the site and soils to determine suitability and treatment requirements.

Licensed design and final inspection

After the site and soil evaluation, a licensed septic designer or professional engineer normally prepares the design for Health District review. Before the installed system is covered, Yakima Health District performs a final inspection to verify that it matches the approved design and as-built record.

Limited owner-builder option for conventional systems

Yakima County states that an owner may design and install a conventional gravity system for the owner’s primary single-family residence under the county homeowner process. That option does not extend to accessory dwelling units, rentals, non-owner-occupied homes, or other septic-system types.

Septic clearance for some building projects

The Health District uses a septic-clearance review as part of building-permit processing for projects such as additions, sheds, pools, or changes that could affect the existing septic system, setbacks, or permitted capacity.

Official sources

SepticScope summarizes public-agency information for planning purposes. The permitting agency's current instructions control if they differ from this guide.