Winthrop Wastewater Treatment Plant
906 Main St, Winthrop, WA 98862 · Okanogan County · Publicly Owned Treatment Works
- Average flow
- 0.05 MGD
- Design flow
- 0.56 MGD
- NPDES permit
- WA0020885
- Administratively continued
- Permit expires
- July 2020
- Population served
- 469
- CWNS 2022
Winthrop Wastewater Treatment Plant is a publicly owned wastewater treatment works in Winthrop, Okanogan County, Washington treating an average of 0.05 million gallons per day against a permitted design capacity of 0.56 MGD, serving about 469 residents. It discharges under NPDES permit WA0020885 (administratively continued), which expires in July 2020, with 40 recorded violations in the last three years.
Treatment technology
One treatment structure or unit process identified at Winthrop Wastewater Treatment Plant.
Available with a free Klarifi account
See the full treatment train at Winthrop Wastewater Treatment Plant: structures, unit processes and planned upgrades, with exact unit counts.
Compliance snapshot (last 3 years)
- Total violations
- 40
- Effluent violations
- 40
Based on NPDES Discharge Monitoring Reports. Full violation history, parameters and discharge data available in the Klarifi platform.
Key contacts
1 verified contact for Winthrop Wastewater Treatment Plant, with validated emails and direct phone numbers.
Unlock 1 verified contact
Names, validated emails and direct phone numbers for decision-makers at Winthrop Wastewater Treatment Plant, plus the full compliance history and discharge data.
Nearby wastewater treatment plants in Washington
Twisp · 8 mi away
0.07 MGD
Okanogan · 28 mi away
0.16 MGD
Omak · 30 mi away
0.54 MGD
Brewster · 32 mi away
0.16 MGD
Tonasket · 37 mi away
0.1 MGD
Bridgeport · 38 mi away
0.15 MGD
Oroville · 46 mi away
0.18 MGD
Chelan · 46 mi away
0.75 MGD
Winthrop Wastewater Treatment Plant: 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 17, 2026.
Wastewater terms: POTW · MGD · NPDES permit · Inflow and infiltration · Biological nutrient removal · Tertiary treatment · all terms