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City of Zillah

Sewage treatment plant, Zillah, Washington. NPDES permit WA0020168, in force until Oct 31, 2030. Last 12 months: no values over a limit. Source: EPA ECHO, Oct 22, 2026.

Reports due
About 15 days after each period: outfall 001 form MM monthly (22 values), outfall IN1 form MM monthly (7 values), outfall 003 form AA yearly
Last report on file
September 2026
Oct 2024 – Sep 2025
0 values over a limit, 0 required values missing, 0 of 25 reports late

Limits in force (36)

ParameterStatisticLimitMonthsOutfall
Temperature, water deg. centigrademaximumreport only (deg C) (alert, not enforceable)all year001
Temperature, water deg. centigrademonthly averagereport only (deg C) (alert, not enforceable)all year001
Oxygen, dissolved [DO]minimumreport only (mg/L) (alert, not enforceable)all year001
Oxygen, dissolved [DO]monthly averagereport only (mg/L) (alert, not enforceable)all year001
BOD, 5-day, 20 deg. Cmonthly average≤ 30 mg/Lall year001
BOD, 5-day, 20 deg. Cweekly average≤ 45 mg/Lall year001
BOD, 5-day, 20 deg. Cmonthly average≤ 122.6 lb/dall year001
BOD, 5-day, 20 deg. Cweekly average≤ 183.9 lb/dall year001
pHmaximum≤ 9 SUall year001
pHminimum≥ 6 SUall year001
Solids, total suspendedmonthly average≤ 30 mg/Lall year001
Solids, total suspendedweekly average≤ 45 mg/Lall year001
Solids, total suspendedmonthly average≤ 122.6 lb/dall year001
Solids, total suspendedweekly average≤ 183.9 lb/dall year001
Nitrogen, ammonia total [as N]maximumreport only (mg/L) (alert, not enforceable)all year001
Nitrogen, ammonia total [as N]monthly averagereport only (mg/L) (alert, not enforceable)all year001
Nitrogen, ammonia total [as N]maximumreport only (lb/d) (alert, not enforceable)all year001
Nitrogen, ammonia total [as N]monthly averagereport only (lb/d) (alert, not enforceable)all year001
BOD, percent removal [total]monthly average minimum≥ 85 %all year001
Coliform, fecal generalmonthly geometric mean≤ 200 #/100mLall year001
Coliform, fecal generalweekly geometric mean≤ 400 #/100mLall year001
Solids, suspended percent removalmonthly average minimum≥ 85 %all year001
Oil and grease, hexane extr methodsingle readingreport only (mg/L) (alert, not enforceable)all year003
Nitrogen, Kjeldahl, total [as N]single readingreport only (mg/L) (alert, not enforceable)all year003
Nitrite + Nitrate total [as N]single readingreport only (mg/L) (alert, not enforceable)all year003
Phosphorus, total [as P]single readingreport only (mg/L) (alert, not enforceable)all year003
Hardness, total [as CaCO3]single readingreport only (mg/L) (alert, not enforceable)all year003
E. colisingle readingreport only (#/100mL) (alert, not enforceable)all year003
Solids, total dissolvedsingle readingreport only (mg/L) (alert, not enforceable)all year003
BOD, 5-day, 20 deg. Cmonthly averagereport only (mg/L) (alert, not enforceable)all yearIN1
BOD, 5-day, 20 deg. Caveragereport only (lb/d) (alert, not enforceable)all yearIN1
Solids, total suspendedmonthly averagereport only (mg/L) (alert, not enforceable)all yearIN1
Solids, total suspendedaveragereport only (lb/d) (alert, not enforceable)all yearIN1
Flowdaily maximumreport only (MGD) (alert, not enforceable)all yearIN1
Flowmonthly averagereport only (MGD) (alert, not enforceable)all yearIN1
Flowmonthly totalreport only (MGD) (alert, not enforceable)all yearIN1

How strict are these limits?

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

Check this month's numbers Email me before each report is due

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On EPA ECHO: Facility report · DMR history

Your permit document is the final word. As JSON: /api/v1/permits/WA0020168 · MCP: https://passage-data.com/mcp