Three Rivers Regional WWTP
Longview, WA · Cowlitz County · Publicly Owned Treatment Works
- Average flow
- —
- Design flow
- 52 MGD
- NPDES permit
- WA0037788
- Administratively continued
- Permit expires
- February 2026
- Population served
- 45,361
- CWNS 2022
Three Rivers Regional WWTP is a publicly owned wastewater treatment works in Longview, Cowlitz County, Washington, serving about 45,361 residents. Treatment on site includes clarifiers. It discharges under NPDES permit WA0037788 (administratively continued), which expires in February 2026, with 0 recorded violations in the last three years.
Treatment technology
Treatment structures identified at this facility. Exact unit counts are available in Klarifi.
Clarifiers
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Compliance snapshot (last 3 years)
- Total violations
- 0
- Effluent violations
- 0
Based on NPDES Discharge Monitoring Reports. Full violation history, parameters and discharge data available in the Klarifi platform.
Capital improvement projects in Longview
Longview's capital improvement plan lists 44 water, sewer and wastewater line items worth $29M starting 2025–2029. The largest budgeted items are shown here.
All water and sewer capital projects in Longview →
| Project | Budget | Years |
|---|---|---|
| Annual Main Replacements | $4,250,000 | 2025–2029 |
| Annual Main Relining | $4,250,000 | 2025–2029 |
| Replace Castleman Line | $2,290,000 | 2029–2029 |
| 2277 48th Pump Station | $2,000,000 | 2028–2029 |
| 5501 Finch Pump Station | $2,000,000 | 2026–2027 |
Full project details — scope, funding source, engineering consultant and the decision-makers behind each project — are available in Klarifi, along with similar wastewater capital projects in other cities.
Key contacts
Decision-makers at Three Rivers Regional WWTP.
No verified contacts on file yet
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Nearby wastewater treatment plants in Washington
Toutle · 17 mi away
0.06 MGD
Ryderwood · 20 mi away
—
Ridgefield · 21 mi away
—
Winlock · 26 mi away
0.15 MGD
Vancouver · 27 mi away
—
Chehalis · 33 mi away
0.03 MGD
Yacolt · 38 mi away
—
Camas · 44 mi away
2.62 MGD
Three Rivers Regional 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 September 11, 2026; facility record last updated July 3, 2025.