WDO inspection

WDO and termite inspections when buying a home in Washington.

In the Puget Sound climate the bigger risk to a wood-frame house is usually moisture — and the carpenter ants, termites and rot fungi that follow it. A general home inspection notices conditions; a wood destroying organism (WDO) inspection is the report that names the organisms, the damage and the conducive conditions. This hub explains how the two fit together.

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Inspector with a flashlight checking wood framing in a damp crawl space — AI-generated concept illustration; not a photo of a specific place or property.

Quick answer

A general home inspection looks at the whole house — roof, structure, systems and safety. A WDO inspection focuses on wood destroying organisms (such as subterranean and dampwood termites, carpenter ants, wood-boring beetles and wood decay fungi) and the conditions that invite them, like wood-to-soil contact and crawl space moisture. In Washington, WDO reports are regulated by the Washington State Department of Agriculture and must be done by a licensed structural pest inspector; many licensed home inspectors also hold that license and include a WDO report. Ask for it in writing before your inspection contingency ends, and use findings — active infestation, damage, conducive conditions — to request repairs, credits or further evaluation.

WSDA

Washington State Department of Agriculture licenses structural pest inspectors

3 findings

Active organisms, damage, and conducive conditions are reported separately

1 contingency

Order the WDO report inside your inspection period

Questions this hub answers

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termite inspection cost
home vs termite inspection difference

Using a WDO inspection when you buy

01
Confirm the license
Ask whether your inspector holds a WSDA structural pest inspector license and will issue a WDO report, or whether you need a separate pest inspection.
02
Make sure the crawl space is accessible
Most findings in older Seattle and Eastside homes are in the crawl space and around the sill plate. An inaccessible area should be listed as not inspected.
03
Read the three categories
Separate active infestation (needs treatment), damage (may need repair or a structural opinion) and conducive conditions (moisture, wood-soil contact, debris) that will cause problems later.
04
Get specialist follow-up
For damage near structural members, ask a contractor or structural engineer for scope and cost before your contingency deadline.
05
Negotiate with evidence
Attach report pages to your request: treatment by a licensed pest control operator, repairs, or a seller credit. Keep the treatment receipts and any warranty.

Home inspection vs WDO inspection

Item	General home inspection	WDO inspection
Scope	Whole house: roof, structure, systems, safety	Wood destroying organisms and conducive conditions
License in Washington	Home inspector license (RCW 18.280)	WSDA structural pest inspector license
Typical findings	Leaks, wiring, roof age, drainage	Carpenter ants, termites, beetles, rot fungi, wood-soil contact
Report format	Inspector's narrative report	WDO report following WSDA standards
Next step	Repair requests or specialist evaluation	Treatment, wood repair and moisture fixes

Rotted siding near a foundation being probed with a screwdriver and moisture meter — AI-generated concept illustration; not a photo of a specific place or property.

Checklist

WDO checklist for buyers

Inspector's WSDA structural pest license confirmed
Crawl space and attic access cleared
Report separates active, damage and conducive conditions
Photos of each finding
Moisture sources identified (gutters, grading, vapor barrier)
Contractor or engineer opinion for structural damage
Treatment proposal from a licensed pest control operator
Repair request or credit sent before the contingency deadline

WDO inspection FAQ

Do I need a termite inspection in Washington?

It is not required by state law for every purchase, but it is strongly advisable for wood-frame homes in the Puget Sound area, where moisture-related pests and rot are common. Some loan programs or lenders may ask for one; check with yours.

Is a WDO inspection the same as a pest inspection?

A WDO inspection is a specific kind of pest inspection focused on organisms that damage wood. It does not cover rodents or general household pests unless the inspector adds them.

What are conducive conditions?

Conditions that make infestation or rot likely: wood touching soil, standing water or high moisture in the crawl space, missing vapor barrier, wood debris, and poor drainage.

What does a WDO inspection cost?

Prices vary by house size, access and whether it is bundled with the home inspection. Ask for a written quote; bundling is common in Washington when the home inspector also holds the pest license.

Sources

Last checked November 13, 2026. Official sources for the key rules on this page; they describe general rules, and your contract, lender, tax adviser, association documents and each agency's current rules control your specific case.