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How to find us

Phone: 206-296-4600
TTY Relay: 711

Toll-free: 800-325-6165

Click here to email us

Instructions to submit a Public Records Request

Certificates of competency

Only individuals with Certificates of Competency are authorized to perform work and maintenance on on-site septic systems. Click on the following certificates of competency for more information.

On-site Wastewater Treatment System Designer or Professional Engineer (Agricultural, Civil or Sanitary)

Master Installer

Associate Installer

Liquid Waste Pumper/Hauler

Onsite System Maintainer