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
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