Yamhill County, Oregon septic permits and requirements

Permitting authority

Yamhill County Planning & Development — Sanitation Program / County Sanitarian, administering Oregon onsite sewage rules

Yamhill County Planning & Development — 503-434-7516; 400 NE Baker Street, 2nd Floor, McMinnville, OR 97128. Sanitarian office hours are by appointment.

Oregon county-agent framework

Oregon DEQ states that under OAR 340-071-0120 it may authorize counties as its agents for onsite-system permitting, including receiving and processing applications, issuing permits, enforcing onsite requirements, and performing required inspections. Oregon also requires sewage-disposal service businesses performing regulated installation or pumping work to hold the applicable state license.

County Sanitarian approval follows land-use approval

Yamhill County states that, after land-use approval, subsurface sewage-disposal approval must be obtained from the County Sanitarian. The county describes this as a two-step process: first determining soil suitability for a drainfield, then obtaining the permit and installing the septic tank and drainfield system.

Site evaluation is required before installation

The county requires a site-evaluation application before a new septic tank and drainfield are installed. The applicant prepares test holes, and county staff investigate the soil to determine whether the proposed drainfield area is suitable for effluent disposal.

Installation permit and county inspection follow soil approval

After soil suitability is approved, Yamhill County requires an onsite disposal permit before installation. The county states that the permitted work is subject to onsite inspections to verify correct installation.

Existing systems can require county evaluation

Yamhill County states that an Existing System Evaluation may be needed for development on parcels of three acres or less or for loan approval. The review can include an onsite investigation and county records review.

Bedroom additions, replacement homes, and failures have separate septic paths

Changing the use of an existing septic system, including adding bedrooms or replacing a home, may require a septic Authorization. A failing system requires a septic repair permit.

County has direct delegated enforcement authority

Yamhill County Code Chapter 10.50 states that the county implements authority delegated by the State of Oregon for onsite septic systems and adopts the applicable statewide onsite rules for local enforcement.

Official sources

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

Report outdated county information

Septic rules, forms and agency pages can change. If you find a broken official link or a county requirement that has changed, send SepticScope feedback and include the current local government source.