Codes & Regulations

The Unified Development Code (UDC) is an integrated set of standards that regulate building and land development within unincorporated areas of Snohomish County. The UDC is a component of the Snohomish County Code (SCC), the larger body of law that governs a wider array of public and private activities.

Please note that while this information is made available for your research use and convenience, it is not an official source for citation to the county code. Errors in electronic conversion or transmission are possible. To ensure that you are viewing the most recent update of a particular section, chapter, or title of the code, or to ask any questions, please contact the Snohomish County Code Reviser at 425-388-3494 or via email. Any person or entity that relies on information obtained from the system does so at his or her own risk.

Snohomish County Code

View the entire Snohomish County Code (SCC).

Development Code

View SCC Title 30 Unified Development Code.

PDS Rules

Read rules and policies on specific code sections or requirements.

Code Interpretations

Download code interpretations for specific code sections or projects. 

For more information on how to request a code interpretation, see Assistance Bulletin #61.

Shoreline Management Program


Learn about SEPA, the state’s environmental review process, including standards and forms.

Comprehensive Plan

Read the Snohomish County Comprehensive Plan.