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Public Health - Seattle & King County

Seller's responsibilities

Public Health- Seattle & King County requires all sellers of properties with onsite sewage systems to have their on-site septic system 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. For more information about this requirement call the Public Health Wastewater Program at 206-477-8050.

Before closing, when a property served by a septic system* is being sold or transferred, the seller must record a Notice of On-site Sewage System Operation and Maintenance Requirements (OSSM)** at the King County Office of Records and Elections. 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).

*A septic system is also referred to as an "on-site sewage system" in official documents, forms and applications.

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