Tamoshan WWTP
Dublin Dr NW, Olympia, WA 98502 · Thurston County · Publicly Owned Treatment Works
- Average flow
- 0.03 MGD
- Design flow
- 0.15 MGD
- NPDES permit
- WA0037290
- Administratively continued
- Permit expires
- November 2022
- Population served
- 288
- CWNS 2022
Tamoshan WWTP is a publicly owned wastewater treatment works in Olympia, Thurston County, Washington treating an average of 0.03 million gallons per day against a permitted design capacity of 0.15 MGD, serving about 288 residents. It discharges under NPDES permit WA0037290 (administratively continued), which expires in November 2022, with 0 recorded violations in the last three years.
Treatment technology
Treatment structures and unit processes at Tamoshan WWTP.
Treatment structure data not yet analyzed for this facility.
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 Olympia
Olympia's capital improvement plan lists 80 water, sewer and wastewater line items worth $99M starting 2025–2031. The largest budgeted items are shown here.
All water and sewer capital projects in Olympia →
| Project | Budget | Years |
|---|---|---|
| East Elevated Storage | $7,700,000 | 2028–2029 |
| 9610 Eastside (Tank) Reservoir Rehabilitation Construction | $6,935,000 | 2026–2028 |
| Percival Creek Sewer Replacement | $6,627,285 | 2027–2028 |
| 9609 Asbestos Cement (AC) and Again Pipe Replacement | $5,000,000 | 2026–2030 |
| Aging Infrastructure Rehabilitation | $3,881,045 | 2025–2030 |
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 Tamoshan WWTP.
No verified contacts on file yet
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Nearby wastewater treatment plants in Washington
Shelton · 11 mi away
0.000000032 MGD
Littlerock · 19 mi away
0.05 MGD
Rochester · 23 mi away
0.17 MGD
Puyallup · 29 mi away
5.2 MGD
Federal Way · 30 mi away
4.96 MGD
Port Orchard · 33 mi away
1.98 MGD
Orting · 34 mi away
0.91 MGD
Montesano · 34 mi away
0.27 MGD
Tamoshan 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 19, 2026; facility record last updated October 6, 2025.
Wastewater terms: POTW · MGD · NPDES permit · Inflow and infiltration · Tertiary treatment · Significant industrial user · all terms