Endicott STP
Margin St, Endicott, WA 99125 · Whitman County · Publicly Owned Treatment Works
- Average flow
- 0.08 MGD
- Design flow
- 0.45 MGD
- NPDES permit
- WA0023981
- Administratively continued
- Permit expires
- June 2015
- Population served
- 412
- CWNS 2022
Endicott STP is a publicly owned wastewater treatment works in Endicott, Whitman County, Washington treating an average of 0.08 million gallons per day against a permitted design capacity of 0.45 MGD, serving about 412 residents. It discharges under NPDES permit WA0023981 (administratively continued), which expires in June 2015, with 5 recorded violations in the last three years.
Treatment technology
Treatment structures and unit processes at Endicott STP.
Treatment structure data not yet analyzed for this facility.
Compliance snapshot (last 3 years)
- Total violations
- 5
- Effluent violations
- 5
Based on NPDES Discharge Monitoring Reports. Full violation history, parameters and discharge data available in the Klarifi platform.
Key contacts
Decision-makers at Endicott STP.
No verified contacts on file yet
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Nearby wastewater treatment plants in Washington
Saint John · 12 mi away
0.07 MGD
Colfax · 15 mi away
0.33 MGD
Oakesdale · 25 mi away
0.09 MGD
Rosalia · 26 mi away
0.11 MGD
Pullman · 28 mi away
2.46 MGD
Palouse · 29 mi away
0.07 MGD
Pomeroy · 32 mi away
0.12 MGD
Tekoa · 35 mi away
0.12 MGD
Endicott 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 October 6, 2025.
Wastewater terms: POTW · MGD · NPDES permit · Inflow and infiltration · Significant industrial user · WWTP · all terms