Dayville STP
45473 US-26, Dayville, OR 97825 · Grant County · Publicly Owned Treatment Works
- Average flow
- 0.01 MGD
- Design flow
- 0.04 MGD
- NPDES permit
- OR0041505
- Administratively continued
- Permit expires
- July 2026
- Population served
- —
- CWNS 2022
Dayville STP is a publicly owned wastewater treatment works in Dayville, Grant County, Oregon treating an average of 0.01 million gallons per day against a permitted design capacity of 0.04 MGD. It discharges under NPDES permit OR0041505 (administratively continued), which expires in July 2026, with 52 recorded violations in the last three years.
Treatment technology
2 treatment structures and unit processes identified at Dayville STP.
Available with a free Klarifi account
See the full treatment train at Dayville STP: structures, unit processes and planned upgrades, with exact unit counts.
Compliance snapshot (last 3 years)
- Total violations
- 52
- Effluent violations
- 10
Based on NPDES Discharge Monitoring Reports. Full violation history, parameters and discharge data available in the Klarifi platform.
Key contacts
Decision-makers at Dayville STP.
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Nearby wastewater treatment plants in Oregon
Mount Vernon · 20 mi away
0.02 MGD
Long Creek · 27 mi away
0.03 MGD
Heppner · 62 mi away
0.13 MGD
Prineville · 68 mi away
1.17 MGD
North Powder · 88 mi away
0.05 MGD
Maupin · 92 mi away
0.06 MGD
Stanfield · 92 mi away
—
Arlington · 93 mi away
0.06 MGD
Dayville 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 3, 2026.
Wastewater terms: POTW · MGD · NPDES permit · Inflow and infiltration · Oxidation ditch · Anaerobic digester · all terms