septic tank with riser

Mason County requires all Onsite Sewage Systems to be current on maintenance requirements prior to transfer of ownership. See below regulation for more details on the requirements. There are no permitted evaluation requirements for property transfers in Mason County served by OSS at this time.

Mason County Title 6.76.070 – Operation and Maintenance of Onsite Sewage Systems:

(5) Transfer of resident ownership shall require a current inspection service report on the status of the on-site sewage system, using the form prescribed by the director.

  1. Current shall mean within three years with a system consisting solely of a septic tank and drainfield and annually for all other on-site septic system.
  2. Service for an on-site sewage system consisting solely of a septic tank and gravity drainfield shall be performed by a Mason County Certified Pumper or a Mason County Certified Operation and Maintenance Specialist. All other on-site sewage systems will require a report from a Mason County Certified Operation and Maintenance Specialist.