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Jun
28

Disposal costs

Information on the 2025 rates and fees to dispose of septage at the septage disposal facility at South Treatment Plant.

The 2025 rates and fees to dispose of septage at the septage treatment facility at South Treatment Plant are as follows:

Disposal Rate  $0.1529 per gallon*
 We weigh each load and charge $0.0183333 per pound discharged. This covers domestic septic tank waste and portable toilet waste, up to 2% solids. 

Note: the disposal rate includes 1.0 cent per gallon on-going surcharge to provide funds for Public Health-Seattle and King County to respond to failing on-site sewage systems (OSS), provide technical support to property owners wit  h OSS, identify and repair prioritized OSS failures, continue “what not to flush” education and outreach, and improve industry reporting.
 Fees Annual fee: $200/year/truck
Initial setup fee: $50/truck

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