Mold Testing in Bothell, WA

When a test is worth booking

• A closet, bedroom or basement smells damp and the surfaces all look clean.
• Paint is bubbling or baseboards are swelling and you want to know whether growth is behind them.
• You are buying in Canyon Park or North Creek and the inspector flagged moisture.
• A leak was dried and repaired, and you want to confirm nothing took hold.

Testing is not needed to prove that a black patch on drywall is mold. EPA's guidance is that sampling is usually unnecessary when growth is visible, and that no federal limits exist to judge a result against.

Local conditions in Bothell

Bothell sits on the Sammamish River, which King County says generally stays within its banks from Woodinville down to Lake Washington. River flooding is not the main driver here. More often it is everyday moisture: a median home built around 1989 and many apartments built since about 2002, all closed up through a long, cool wet season. Tight construction holds shower steam and cooking moisture unless fans run, and cold window frames collect water on winter mornings.

Bothell straddles the King and Snohomish county line, so which county health department serves you depends on your address. King County residents can reach Public Health - Seattle & King County for indoor air and mold consultations.

Renters should know the city's Code Compliance Division handles unsafe structures and building code violations but does not enforce tenant and landlord disputes; it points renters to the state Attorney General's landlord-tenant resources and RCW 59.18. Give your landlord written notice of the leak or moisture problem before spending your own money on testing. This is general information, not legal advice.

What affects cost

Angi's 2026 national data lists basic air tests at $250 to $350 and swab tests at $200 to $300. HomeGuide's 2026 national figures add bulk samples at $100 to $350 each. Bothell prices vary with the number of samples, how many rooms are checked, crawl space or attic access, and lab speed.

What happens when you call

You will be connected with an independent local inspector or mold company. Ask whether they take an outdoor control sample, whether moisture readings are included, and how results are explained. If remediation follows, Angi recommends a separate company for clearance testing, and any contractor doing the repairs should be registered with Washington L&I, which you can check on L&I's Verify tool.