King County South WWTP
1200 Monster Rd SW, Renton, WA 98057 · King County · Publicly Owned Treatment Works
- Average flow
- 74.4 MGD
- Design flow
- —
- NPDES permit
- WAR002511
- Effective
- Permit expires
- December 2029
- Population served
- 791,766
- CWNS 2022
King County South WWTP is a publicly owned wastewater treatment works in Renton, King County, Washington treating an average of 74.4 million gallons per day, serving about 791,766 residents. It discharges under NPDES permit WAR002511 (effective), which expires in December 2029, with 3 recorded violations in the last three years. EPA has recorded 2 formal enforcement actions naming the plant, the latest in December 2009.
Treatment technology
2 treatment structures and unit processes identified at King County South WWTP.
Available with a free Klarifi account
See the full treatment train at King County South WWTP: structures, unit processes and planned upgrades, with exact unit counts.
Compliance snapshot (last 3 years)
- Total violations
- 3
- Effluent violations
- 1
Based on NPDES Discharge Monitoring Reports. Full violation history, parameters and discharge data available in the Klarifi platform.
EPA enforcement history
Federal civil enforcement cases, compliance inspections and informal actions recorded for King County South WWTP in EPA's ICIS system.
- Formal actions
- 2
- 0 since FY2020
- Penalties assessed
- $2,150
- all cases
- Compliance actions
- $2,050
- required by EPA orders
- EPA inspections
- 1
- latest Aug 2009
Latest case · Dec 2009
King County - South Treatment Plant
Administrative order · CAA, Prevention of Accidental Release/Risk Management Plans (RMPs) · Final Order With Penalty · Penalty $2,000 · Compliance actions $2,000
EPA's description of the case:
“violations of CAA Section 112r”
Source: EPA ECHO, civil enforcement case 10-2010-0029.
Full case history with a free Klarifi account
Every action against King County South WWTP with dates, milestones, violation types and EPA's complete case summaries, plus inspections and informal actions.
Key contacts
2 verified contacts for King County South WWTP, with validated emails and direct phone numbers.
Unlock 2 verified contacts
Names, validated emails and direct phone numbers for decision-makers at King County South WWTP, plus the full compliance history and discharge data.
Nearby wastewater treatment plants in Washington
Seattle · 5 mi away
3.6 MGD
Seattle · 6 mi away
3.03 MGD
Federal Way · 12 mi away
4.96 MGD
Port Orchard · 16 mi away
0.22 MGD
Seattle · 16 mi away
106.93 MGD
Bainbridge Island · 17 mi away
0.63 MGD
Port Orchard · 18 mi away
1.98 MGD
Puyallup · 19 mi away
5.2 MGD
King County South WWTP: frequently asked questions
Sources and methodology
Flow, permit and violation figures come from the EPA's ICIS-NPDES discharge monitoring records. Population served comes from the Clean Watersheds Needs Survey 2022. Treatment structures are identified by Klarifi's review of aerial imagery, and capital improvement projects are extracted from published municipal budget documents. Violations are counted over the last three years of monitoring reports.
Data refreshed October 26, 2026; facility record last updated July 3, 2025.
Wastewater terms: POTW · MGD · NPDES permit · Inflow and infiltration · Equalization tank · Centrate · all terms