Anyone wishing to install, modify, or repair an onsite sewage system is required to first obtain a permit from Mason County Community Services, Environmental Health. Permitted activities include:

New Residential and Commercial Onsite Sewage Systems, Sewage System Repairs and Replacements, Sewage System Upgrades, RV Holding Tanks, and Sewage Tank Replacements.


Other Services:

The Mason County Onsite Sewage program staff are responsible for review of several other permitted activities, including:

Property Evaluations, Winter Observations, Review of an Existing OSS, Building Permits, Subdivisions, Large Plats, Short Plats, Boundary Line Adjustments, Pre-application Meetings, and Change in Tenants.

Homeowner Installation Activities:

A homeowner wishing to perform installation, modification, and/or repair work to an Onsite Sewage System must first obtain approval from Mason County Community Services, Environmental Health. Homeowner installation work may be permittable providing specific conditions and requirements are met. Not all situations and work are approved for homeowner installation. Contact Environmental Health staff for more information and requirements. Failure to obtain proper permission and follow Mason County policies may result in fines and additional costs related to work.