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Coulee Dam, Town of

Sewage treatment plant, Coulee Dam, Washington. NPDES permit WA0020281 expired Nov 30, 2022; its limits still apply. Last 12 months: no values over a limit. Source: EPA ECHO, Oct 22, 2026.

Reports due
About 15 days after each period: form A monthly (34 values)
Last report on file
September 2026
Oct 2024 – Sep 2025
0 values over a limit, 0 required values missing, 0 of 12 reports late

Limits in force (34)

ParameterStatisticLimitMonths
BOD, 5-day, 20 deg. Cmonthly average≤ 30 mg/Lall year
BOD, 5-day, 20 deg. Cweekly average≤ 45 mg/Lall year
BOD, 5-day, 20 deg. Cmonthly average≤ 48.8 lb/dall year
BOD, 5-day, 20 deg. Cweekly average≤ 73.1 lb/dall year
BOD, 5-day, 20 deg. Cmonthly averagereport only (mg/L)all year
BOD, 5-day, 20 deg. Cmonthly average≤ 30 mg/Lall year
BOD, 5-day, 20 deg. Cweekly average≤ 45 mg/Lall year
BOD, 5-day, 20 deg. Cmonthly average≤ 125 lb/dall year
BOD, 5-day, 20 deg. Cweekly average≤ 187 lb/dall year
pHinstantaneous minimum≥ 6.5 SUall year
pHinstantaneous maximum≤ 8.5 SUall year
Solids, total suspendedmonthly average≤ 30 mg/Lall year
Solids, total suspendedweekly average≤ 45 mg/Lall year
Solids, total suspendedmonthly average≤ 48.8 lb/dall year
Solids, total suspendedweekly average≤ 73.1 lb/dall year
Solids, total suspendedmonthly averagereport only (mg/L)all year
Solids, total suspendedmonthly average≤ 30 mg/Lall year
Solids, total suspendedweekly average≤ 45 mg/Lall year
Solids, total suspendedmonthly average≤ 125 lb/dall year
Solids, total suspendedweekly average≤ 187 lb/dall year
Nitrogen, ammonia total [as N]monthly averagereport only (mg/L)all year
Nitrogen, ammonia total [as N]weekly averagereport only (mg/L)all year
Fecal coliform, MPN, EC med, 44.5 Cgeometric mean≤ 50 #/100mLall year
Floating solids, waste or visible foam-visualmonthly maximum≤ 0 N=0;Y=1all year
Flow, in conduit or thru treatment plantmonthly averagereport only (MGD)all year
Flow, in conduit or thru treatment plantdaily maximumreport only (MGD)all year
Chlorine, total residualmonthly average≤ .5 mg/Lall year
Chlorine, total residualweekly average≤ .75 mg/Lall year
Chlorine, total residualmonthly average≤ 2.1 lb/dall year
Chlorine, total residualweekly average≤ 3.1 lb/dall year
Enterococcigeometric mean≤ 16 #/100mLall year
Enterococciinstantaneous maximum≤ 75 #/100mLall year
BOD, 5-day, percent removalmonthly average minimum≥ 85 %all year
Solids, suspended percent removalmonthly average minimum≥ 85 %all year

How strict are these limits?

Cited limits by parameter: Washington's rules and the federal ones.

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On EPA ECHO: Facility report · DMR history

Your permit document is the final word. As JSON: /api/v1/permits/WA0020281 · MCP: https://passage-data.com/mcp