Skip to main content

Thurston County, Washington

The content on the Thurston County website is currently provided in English. We are providing the “Translation” for approximately 10 languages. The goal of the translation is to provide visitors with limited English proficiency to access information on the website in other languages. The translations do not translate all types of documents, and it may not give you an exact translation all the time. The translations are made through an automated process, which may not result in accurate or precise translations, particularly of technical and legal terminology.

What Inspectors Look For & How to Prepare

If you apply for a permit, county inspectors come on property, in-person to see if environmental conditions on the property match county maps, to inspect the construction site, and to see if your project meets code. 


Building Inspections - Done During & After Development 

Regulated Environmental Area Inspections

After you submit an application, county inspectors look to see if actual property conditions match what is shown on county maps and/or to make sure a project is far enough away from these areas to meet code. 

  • Critical Area Inspections
    • Required by County Code Title 24: Critical Areas Ordinance  
    • Acquifer recharge areas (land drains into acquifer) - No prep necessary. Inspectors check soil type and known location of acquifer. 
    • Flood Hazard areas - No prep necessary. Inspectors check entire parcel for signs of past flooding. 
    • Landslide Hazard areas - No prep necessary. Inspectors check slopes, soils, vegetation and other ground conditions. 
    • Mima mounds, oak trees, prairie plants (listed in code) - Prepare for prairie plant inspection by mowing so inspectors can see the ground. See mowing chart and inspection details on Prairie Plant Inspections page. No other preps necessary.
    • Wetlands - No prep necessary. Inspectors check entire parcel for signs of seasonal wetlands, soils, wetland vegetation. 
  • Habitat Conservation Plan Inspections 
    • Required by County Code Title 17: Environment 
    • Oregon spotted frog - No prep necessary. Inspectors may check wetlands and ground conditions during rainy season. 
    • Oregon vesper sparrow & Taylors checkerspot butterfly. Generally, inspections not required.
    • Mazama pocket gopher, No preps necessary. Generally, inspections not required, but biologist may come on-site to verify that actual conditions match those on the county HCP map.
  • Shoreline Master Program Inspections
  • Environmental Inspections Conducted by
    • County biologists in the Community Planning, and Development Services divisions of Community Planning & Economic Development Department
    • Other inspections/reports: May also require you to hire expert environmental inspections and reports detailing location, size and type of regulated area. 

Septic, Well & Water Inspections - Done Before Development Begins


  • Required by sanitary code. Details in County Sanitary Code Article III: Drinking Water Supplies (PDF) |  Article IV: Sewage Disposal (PDF)
  • What's regulated: septic systems, tanks and drainfields, wells, well water sources, well testing. 
  • Inspectors come on-site to test soils, geology of the site, and may verify that systems meet code or match the information/drawings submitted.
  • Inspections by Environmental Health Division of Public Health & Social Services Department
  • Other inspections/reports: May also require expert septic and well inspections, testing and reports. 


Stormwater Drainage, Erosion Control, Driveways/Road Access Inspections (Development Review Inspections) - Done During & After Development

  • What's inspected:
    • Construction site -  to make all property corners are marked; to ensure trucks aren't tracking mud onto the road. Use straw wattle & silt fencing as erosion control measure. (Miriam has a PDF).
    • Driveways & road access - to make sure your driveway won't cross a drainage ditch; to make sure development doesn't cause water from your property to flood any roads or neighbors, to make sure drivers entering/existing your driveway can see oncoming traffic, When approved. You'll get an Encroachment Permit. 
    • Stormwater drainage & erosion from rainwater runoff - to make sure downspouts are properly installed and water is draining in a way that meets code.
    • Sedimentation and Erosion Control Excavation for footings should be complete, and all required reinforcing steel should be in place. Any required forms and all bedding materials for an all-weather wood foundation system should be in place.
  • Details in County Code Title 13: Roads & Bridges  |  County Code Title 14: Buildings & Construction  }  County Code Title 15: Public Works  | 2022 Drainage Manual
  • Inspections done by Development Review division of Public Works Department
  • Other inspections/reports: May also require expert stormwater drainage inspections, plans and drawings. 
  • When inspections are approved, you'll be notified by staff.

Elected Officials Adopt All Code Regulations & Inspection Requirements

All County regulations, Codes, Ordinances and inspection requirements are adopted by the Board of County Commissioners before being implemented. All codes go through the County's rigorous Community Planning process that includes public input and hearings, review of and recommendation by citizen committees prior to Commissioner adoption.