The purpose of On-site Septic System (OSS) Program is to ensure proper treatment and disposal of wastewater to protect our environment and drinking water. We issue septic permits, inspect final septic installations, and investigate complaints associated with On-site Sewage systems.

Septic System Failure

For information on failing septic systems, please see DOH's Signs of Septic System Failure page.

SetbacksSite Plan ChecklistWaiver RequestSample Shared Well (Joint Use) AgreementCovenant Examples (100’ radius)Group A or B Water Systems HandoutGroup B Water System Guidance

• On-site Sewage Systems Chapter 246-272A WAC

• EPA Website

• Chelan County Community Development
• Douglas County Land Services
• Eviction Help

Effective April 1, 2025

All provisions of the rule excluding changes to WAC 246-272A-0110, the Maintenance Service Provider approval requirement, and Property Transfer Inspection requirement. Click here to learn more.

WAC 246-272A Code Revision

Resources

SepticSmart Quick Tip videos

SepticSmart Long Homeowner GuideSepticSmart Long Homeowner Guide ESPSepticSmart Top 10 Ways to be a Good Septic OwnerSepticSmart Top 10 Ways to be a Good Septic Owner ESPSepticSmart InfographicSepticSmart Infographic ESPSepticSmart Do’s and Don’ts of Your Septic SystemSepticSmart Do’s and Don’ts of Your Septic System ESPSeptic Tank Lid SafetyGovernor's SepticSmart Week Proclamation 2025