Realtor Septic Education

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Home Sales and transfers of properties with septic systems in King County

Public Health- Seattle & King County requires all sellers of properties with onsite sewage systems (Septic Tank Systems) to have their on-site Septic Tank System(OSS) inspected by a King County licensed On-Site System Maintainer (OSM).  The inspection must be completed and a copy of the report must be given to both the buyer and Public Health before the transfer of title. The OSM must use the King County reporting forms when submitting the inspection report packet to Public Health.

A-1 Environmental staff holds the following certifications and licenses:

  • Septic Tank Pumping Professional
  • On-Site Septic System Maintainer (OSM)
  • Certified OSS (Onsite Septic System) Septic System Inspection Professional
  • Certified Master Installer (New System Installation & Repair Professional)

King County OSS Septic System Inspection filing fee $106.00 This fee is collected by your (O&M) Septic System Inspection Professional (check made out to PHSKC Health) from the homeowner (or whoever is paying) and paid directly to King County – This is NOT a septic system inspection fee charged by A-1 Environmental, this is a King County fee…… but we must have the funds prior to submitting  the O & M Septic System Inspection Sale Certification paperwork to the King County Health Dept.

Find out more about Real Estate Septic System Inspection Sale Certifications in King County: King County Real Estate Septic System Inspection page

Before closing, the seller must record a “Notice of On-site Sewage System Operation and Maintenance Requirements” (OSSM)* at the King County Recorders Office. This is a document that acknowledges the property is served by a septic system and describes the owner’s responsibilities for maintaining the system. The seller gives a copy of the recorded (OSSM)* to the buyer prior to closing.  A declaration of receipt of the recorded (OSSM)* should be signed by the seller and buyer for their records (King County does not need a copy of this declaration of receipt).

*OSSM – is also known as Form 22U by the Northwest Multiple Listing Service

A Septic System is also referred to as an “On-site Sewage System” in official documents, forms and applications.  The following documents can be downloaded for your knowledge and use when selling your home in King County.

Downloadable Adobe format King County Forms: