Enumclaw STP
451 Semanski St S, Enumclaw, WA 98022 · King County · Publicly Owned Treatment Works
- Average flow
- 1.85 MGD
- Design flow
- —
- NPDES permit
- WA0020575
- Effective
- Permit expires
- June 2030
- Population served
- 12,500
- CWNS 2022
Enumclaw STP is a publicly owned wastewater treatment works in Enumclaw, King County, Washington treating an average of 1.85 million gallons per day, serving about 12,500 residents. It discharges under NPDES permit WA0020575 (effective), which expires in June 2030, with 0 recorded violations in the last three years.
Treatment technology
One treatment structure or unit process identified at Enumclaw STP.
Available with a free Klarifi account
See the full treatment train at Enumclaw STP: structures, unit processes and planned upgrades, with exact unit counts.
Compliance snapshot (last 3 years)
- Total violations
- 0
- Effluent violations
- 0
Based on NPDES Discharge Monitoring Reports. Full violation history, parameters and discharge data available in the Klarifi platform.
Key contacts
2 verified contacts for Enumclaw STP, with validated emails and direct phone numbers.
Unlock 2 verified contacts
Names, validated emails and direct phone numbers for decision-makers at Enumclaw STP, plus the full compliance history and discharge data.
Nearby wastewater treatment plants in Washington
Carbonado · 8 mi away
0.03 MGD
Orting · 11 mi away
0.91 MGD
Puyallup · 15 mi away
5.2 MGD
Federal Way · 20 mi away
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Renton · 22 mi away
74.4 MGD
Seattle · 24 mi away
3.6 MGD
Eatonville · 26 mi away
0.24 MGD
Seattle · 27 mi away
3.03 MGD
Enumclaw STP: 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 August 14, 2026.
Wastewater terms: POTW · MGD · NPDES permit · Inflow and infiltration · Tertiary treatment · Significant industrial user · all terms