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.

Site Plan ChecklistSample 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

Resources

SepticSmart Quick Tip videos

SepticSmart Long Homeowner GuideSepticSmart Long Homeowner Guide ESPSepticSmart InfographicSepticSmart Infographic ESPSepticsmart_top_10_flyer_final_ENGL.pdfSepticsmart_top_10_flyer_041918_SPN.pdfSepticSmart 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