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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.

The county's Critical Areas Determination (CAD) report is not a permit.  It's an on-property, in-person inspection of a property. A biological expert inspects the entire parcel or property to see if regulated critical and/or environmental areas are on it. They then prepare a report detailing the location, type and size of the areas. These reports are used to help permit applicants plan their project to avoid putting buildings and development in or near these areas or their buffers, and to help identify which land-use regulations apply to the project.


When to apply for a CAD and how long it takes


  • The CAD report is a good option for people who are trying to find out if the critical and/or environmental areas on a property may affect future building or development plans. Apply anytime.
  • It's also helpful if you want the county to review your expert reports and provide a county determination about the critical areas on your property. Apply after you get your environmental reports back from your consultants. Submit your reports with a completed CAD application. 
  • If you know your property has critical or regulated environmental areas, or you found these areas mapped on your property when looking at county maps, it's best to hire environmental experts to prepare environmental and critical area reports. You'll need these expert reports to help you site and design your project, complete forms, etc.  

How to Apply

Go to the Applications & Forms page and look for Critical Area Determination (CAD) at the top of the page. There you'll find the forms and instructions. You'll need a Site Plan in addition to the forms, but instructions are on the forms.