Rosalia STP
216 1st St W, Rosalia, WA 99170 · Whitman County · Publicly Owned Treatment Works
- Average flow
- 0.11 MGD
- Design flow
- —
- NPDES permit
- WA0044687
- Administratively continued
- Permit expires
- February 2021
- Population served
- 550
- CWNS 2022
Rosalia STP is a publicly owned wastewater treatment works in Rosalia, Whitman County, Washington treating an average of 0.11 million gallons per day, serving about 550 residents. It discharges under NPDES permit WA0044687 (administratively continued), which expires in February 2021, with 22 recorded violations in the last three years. EPA has recorded 1 formal enforcement action naming the plant, the latest in January 2025.
Treatment technology
One treatment structure or unit process identified at Rosalia STP.
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See the full treatment train at Rosalia STP: structures, unit processes and planned upgrades, with exact unit counts.
Compliance snapshot (last 3 years)
- Total violations
- 22
- Effluent violations
- 22
Based on NPDES Discharge Monitoring Reports. Full violation history, parameters and discharge data available in the Klarifi platform.
EPA enforcement history
Federal civil enforcement cases, compliance inspections and informal actions recorded for Rosalia STP in EPA's ICIS system.
- Formal actions
- 1
- 1 since FY2020
- Penalties assessed
- $488
- all cases
- Compliance actions
- $15,000
- required by EPA orders
- EPA inspections
- 0
- none on record
Latest case · Jan 2025
TOWN OF ROSALIA WWTP - ESA (CWA NPDES)
Administrative order · CWA, NPDES Permit Violations · Final Order With Penalty · Penalty $488 · Compliance actions $15,000
EPA's description of the case:
“On January 2, 2025, Region 10 filed an expedited settlement agreement resolving CWA violations of the NPDES permit covering the Town of Rosalia's wastewater facility (Rosalia, WA). Alleged violations…”
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Source: EPA ECHO, civil enforcement case 10-2024-0244.
Full case history with a free Klarifi account
Every action against Rosalia STP with dates, milestones, violation types and EPA's complete case summaries, plus inspections and informal actions.
Key contacts
Decision-makers at Rosalia STP.
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Nearby wastewater treatment plants in Washington
Oakesdale · 11 mi away
0.09 MGD
Spangle · 13 mi away
0.02 MGD
Tekoa · 14 mi away
0.12 MGD
Fairfield · 14 mi away
0.06 MGD
Saint John · 14 mi away
0.07 MGD
Rockford · 18 mi away
0.07 MGD
Colfax · 24 mi away
0.33 MGD
Endicott · 26 mi away
0.08 MGD
Rosalia 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 · Filter press · FOG · all terms