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.

If you apply for a building permit, the County checks its map to see if the project property has White Oak, Mima Mounds or the prairie soils or plants listed in the County's Critical Areas Ordinance (CAO).  If it does, the entire parcel is inspected.

  • Prairie Plant Inspection season is opened in April and run through mid-September, depending on weather conditions.
  • Applications are accepted year-round, but per CAO code, the inspection window is spring to early fall. 

Basic Inspection Information  

  • Prairie plant inspections start mid-April and end mid-September. (Applications are accepted and prescreened year-round). 
  • Properties are visited one or two times, depending on site conditions. Entire parcel is inspected.
  • Follow mowing requirements as shown on the back of this fact sheet carefully so ground is visible. No mowing three weeks before inspection. Mowing may lead to reinspection, which could cause delays in processing your application.
  • Don’t dig, move dirt, pull stumps, add gravel or level mounds until AFTER project is permitted.
  • An inspector walks the entire property looking for prairie plants, White Oak and Mima Mounds as listed in the CAO (linked above).
  • After the site visit, the project status is updated in the online permit status lookup, and the project case manager is notified. 

General prairie criteria

  • 3 or more CAO-listed prairie plants close together (about 16 feet). Or
  • 25 individual CAO listed plants or species on the project site. Or
  • Presence of plants that provide food or shelter for the Taylors checkerspot butterfly (a federally endangered species) or other protected butterfly species. Or
  • Presence of rare plants classified as such by Washington's Natural Heritage Program.

Some applicants modified their plans a bit to avoid mitigation requirements. Others applied for a Reasonable Use Exception (forms & information on the Permit Applications & Forms page). Others worked with prairie plant biologists to create a mitigation plan to replace prairie plants onsite that will be lost to the building project. Staff can discuss the options with you. All applications are processed in accordance with the county’s Critical Area Ordinance