What is the address of Tonasket POTW?

The address on the plant’s EPA facility record is 500 Railroad Ave S, Tonasket, WA 98855, in Okanogan County. Its coordinates are 48.7020, -119.4462. For some plants the record holds the utility’s mailing address rather than the plant gate.

How much wastewater does Tonasket POTW treat?

Tonasket POTW treats an average of 0.1 MGD.

What treatment technology does Tonasket POTW use?

Klarifi has identified one treatment structure or unit process at the Tonasket facility. The full treatment train, with exact unit counts, is shown in Klarifi with a free account.

What is the NPDES permit for Tonasket POTW?

The facility discharges under NPDES permit WA0052337, currently effective, expiring April 2031.

Is Tonasket POTW in compliance?

Discharge monitoring reports show 9 violations at Tonasket POTW in the last three years, 9 of them effluent limit exceedances. The full history is available in Klarifi.

Who operates Tonasket POTW and how do I contact them?

Tonasket POTW is a publicly owned treatment works in Tonasket, Washington. Klarifi lists 1 verified decision-maker contact for this facility, available with a free trial.

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Tonasket POTW

500 Railroad Ave S, Tonasket, WA 98855 · Okanogan County · Publicly Owned Treatment Works

Average flow: 0.1 MGD

Design flow: —

NPDES permit: WA0052337; Effective

Permit expires: April 2031

Population served: 1,173; CWNS 2022

Tonasket POTW is a publicly owned wastewater treatment works in Tonasket, Okanogan County, Washington treating an average of 0.1 million gallons per day, serving about 1,173 residents. It discharges under NPDES permit WA0052337 (effective), which expires in April 2031, with 9 recorded violations in the last three years.

Treatment technology

One treatment structure or unit process identified at Tonasket POTW.

Available with a free Klarifi account

See the full treatment train at Tonasket POTW: structures, unit processes and planned upgrades, with exact unit counts.

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Compliance snapshot (last 3 years)

Total violations: 9

Effluent violations: 9

Based on NPDES Discharge Monitoring Reports. Full violation history, parameters and discharge data available in the Klarifi platform.

Key contacts

1 verified contact for Tonasket POTW, with validated emails and direct phone numbers.

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Names, validated emails and direct phone numbers for decision-makers at Tonasket POTW, plus the full compliance history and discharge data.

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Nearby wastewater treatment plants in Washington

Oroville Wastewater Treatment Plant

Oroville · 15 mi away

0.18 MGD

Omak Wastewater Treatment Plant

Omak · 21 mi away

0.54 MGD

Okanogan WWTP

Okanogan · 25 mi away

0.16 MGD

Winthrop Wastewater Treatment Plant

Winthrop · 37 mi away

0.05 MGD

Twisp WWTP

Twisp · 39 mi away

0.07 MGD

Brewster STP

Brewster · 45 mi away

0.16 MGD

Bridgeport WWTP

Bridgeport · 48 mi away

0.15 MGD

Grand Coulee WWTP

Grand Coulee · 56 mi away

0.2 MGD

Tonasket POTW: 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 September 14, 2026.

Wastewater terms: POTW · MGD · NPDES permit · Inflow and infiltration · Activated sludge · Oxidation ditch · all terms

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