How much wastewater does Ennis WWTP treat?

Ennis WWTP treats an average of 0.44 MGD and is permitted for a design flow of 0.24 MGD.

What treatment technology does Ennis WWTP use?

Klarifi has identified 2 treatment structures and unit processes at the Ennis facility. The full treatment train, with exact unit counts, is shown in Klarifi with a free account.

What is the NPDES permit for Ennis WWTP?

The facility discharges under NPDES permit MT0030732, currently administratively continued, expiring April 2019.

Is Ennis WWTP in compliance?

Discharge monitoring reports show 8 violations at Ennis WWTP in the last three years, 7 of them effluent limit exceedances. The full history is available in Klarifi.

Who operates Ennis WWTP and how do I contact them?

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

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Ennis WWTP

Ennis, MT 59729 · Madison County · Publicly Owned Treatment Works

Average flow: 0.44 MGD

Design flow: 0.24 MGD

NPDES permit: MT0030732; Administratively continued

Permit expires: April 2019

Population served: 1,371; CWNS 2022

Ennis WWTP is a publicly owned wastewater treatment works in Ennis, Madison County, Montana treating an average of 0.44 million gallons per day against a permitted design capacity of 0.24 MGD, serving about 1,371 residents. It discharges under NPDES permit MT0030732 (administratively continued), which expires in April 2019, with 8 recorded violations in the last three years.

Treatment technology

2 treatment structures and unit processes identified at Ennis WWTP.

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

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Compliance snapshot (last 3 years)

Total violations: 8

Effluent violations: 7

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

Key contacts

1 verified contact for Ennis WWTP, with validated emails and direct phone numbers.

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

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Nearby wastewater treatment plants in Montana

Twin Bridges WWTF

Twin Bridges · 32 mi away

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Willow Creek Wastewater Treatment Plant

Willow Creek · 33 mi away

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Bozeman Water Treatment Plant

Bozeman · 38 mi away

0.09 MGD

River Rock Subdivision

Belgrade · 38 mi away

0.16 MGD

Three Forks WWTF

Three Forks · 38 mi away

0.44 MGD

City Of Bozeman WWTP

Bozeman · 41 mi away

6.55 MGD

City Of Belgrade- Belgrade Wastewater Treatment Plant

Belgrade · 41 mi away

0.36 MGD

Manhattan WWTF

Manhattan · 41 mi away

0.29 MGD

Ennis 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 November 7, 2025.

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

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