Passage Data · Check a report · Use it from your AI

Mackay, City of

Sewage treatment plant, Mackay, Idaho. NPDES permit ID0023027 expired May 31, 2023; its limits still apply. Last 12 months: over a limit 4 times (last September 2026). Source: EPA ECHO, Oct 22, 2026.

Reports due
About 20 days after each period: outfall 001 form A monthly (22 values), outfall 001 form C monthly (8 values), outfall REC form Q quarterly (5 values), outfall 001 form Y1 yearly
Last report on file
September 2026
Oct 2024 – Sep 2025
1 value over a limit, 0 required values missing, 0 of 29 reports late

Last 12 months (Oct 1, 2025 – Sep 30, 2026)

Period endingParameterReportedLimitOver by
May 2026Solids, total suspended, monthly average64.5 mg/L≤ 45 mg/L43%
August 2026Solids, suspended percent removal, monthly average minimum59 %≥ 65 %17%
September 2026Solids, suspended percent removal, monthly average minimum61 %≥ 65 %11%
September 2026Solids, total suspended, monthly average75 mg/L≤ 45 mg/L67%

Limits in force (43)

ParameterStatisticLimitMonthsOutfall
Temperature, water deg. centigradeweekly averagereport only (deg C)all year001
Temperature, water deg. centigradedaily maximumreport only (deg C)all year001
Temperature, water deg. centigradeinstantaneous maximumreport only (deg C)all year001
Oxygen, dissolved [DO]instantaneous minimumreport only (mg/L)all year001
BOD, 5-day, 20 deg. Cmonthly average≤ 45 mg/Lall year001
BOD, 5-day, 20 deg. Cweekly average≤ 65 mg/Lall year001
BOD, 5-day, 20 deg. Cmonthly average≤ 68 lb/dall year001
BOD, 5-day, 20 deg. Cweekly average≤ 98 lb/dall year001
BOD, 5-day, 20 deg. Cmonthly averagereport only (mg/L)all year001
pHinstantaneous minimum≥ 6.5 SUall year001
pHinstantaneous maximum≤ 9 SUall year001
Solids, total suspendedmonthly average≤ 45 mg/Lall year001
Solids, total suspendedweekly average≤ 65 mg/Lall year001
Solids, total suspendedmonthly average≤ 65 lb/dall year001
Solids, total suspendedweekly average≤ 98 lb/dall year001
Solids, total suspendedmonthly averagereport only (mg/L)all year001
Nitrogen, ammonia total [as N]monthly average≤ 10 mg/Lall year001
Nitrogen, ammonia total [as N]daily maximum≤ 25 mg/Lall year001
Nitrogen, ammonia total [as N]annual maximumreport only (mg/L)all year001
Nitrogen, ammonia total [as N]monthly average≤ 15 lb/dall year001
Nitrogen, ammonia total [as N]daily maximum≤ 38 lb/dall year001
Nitrogen, Kjeldahl, total [as N]annual maximumreport only (mg/L)all year001
Nitrite + Nitrate total [as N]annual maximumreport only (mg/L)all year001
Phosphorus, total [as P]annual maximumreport only (ug/L)all year001
Oil and greaseannual maximumreport only (mg/L)all year001
E. coli, MTEC-MFmonthly geometric mean≤ 126 #/100mLall year001
E. coli, MTEC-MFinstantaneous maximum≤ 406 #/100mLall year001
Floating solids, waste or visible foam-visualmonthly maximum≤ 0 N=0;Y=1all year001
Flow, in conduit or thru treatment plantmonthly averagereport only (MGD)all year001
Flow, in conduit or thru treatment plantdaily maximumreport only (MGD)all year001
Chlorine, total residualmonthly average≤ 420 ug/Lall year001
Chlorine, total residualdaily maximum≤ 470 ug/Lall year001
Chlorine, total residualannual maximumreport only (ug/L)all year001
Chlorine, total residualmonthly average≤ .63 lb/dall year001
Chlorine, total residualdaily maximum≤ .71 lb/dall year001
Solids, total dissolvedannual maximumreport only (mg/L)all year001
BOD, 5-day, percent removalmonthly average minimum≥ 65 %all year001
Solids, suspended percent removalmonthly average minimum≥ 65 %all year001
Temperature, water deg. centigradeinstantaneous maximumreport only (deg C)all yearREC
Stream flow, instantaneousinstantaneous minimumreport only (cfs)all yearREC
pHinstantaneous minimumreport only (SU)all yearREC
pHinstantaneous maximumreport only (SU)all yearREC
Nitrogen, ammonia total [as N]instantaneous maximumreport only (mg/L)all yearREC

How strict are these limits?

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

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

· Save this facility as a site · Superfund sites nearby · Your permits on one board

On EPA ECHO: Facility report · DMR history

Your permit document is the final word. As JSON: /api/v1/permits/ID0023027 · MCP: https://passage-data.com/mcp