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The 2024 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