King County South Treatment Plant septage tip

$0.1745

Source: King County Wastewater Treatment Division — Septage disposal costs

Effective date: January 1 through December 31, 2026 (as the official disposal-costs page prints).

Checked 2026-08-22. Next check 2026-08-29.

That is $0.1745 per gallon for domestic septic tank waste and portable toilet waste, up to 2% solids. The same page prints a weigh-each-load charge of $0.0209232 per pound discharged. The $0.01 per gallon on-going surcharge for Public Health–Seattle and King County OSS work is inside this cell, not added on top.

Official rate	Fee
Per pound (same load, weighed)	$0.0209232 per pound
Load minimum	None printed
Annual fee	$200 per year per truck
Initial setup fee	$50 per truck
$0.01 per gallon surcharge	Inside the $0.1745 cell