SUN PRAIRIE City of

NPDES permit WI0020478 · Major POTW · expired, expires 2023-09-30 · EPA's file as of 2026-09-19

Check this month's numbers before you file
Watch this permit — $79 a month. Every Monday, from EPA's newest files: the next report due and when, whether EPA's file holds your last one, any change to this permit's limits or status, and the renewal date.

This permit expired on 2023-09-30 and is expired: its last limits keep applying until a new permit is issued, and EPA still expects the reports.

EPA's record, 2025-09-01 to 2026-08-31

0values over a limit
16required values missing, on 10 form(s)
2of 28 forms filed late

Last period with anything received: 2026-06-30.

Reporting

Reports are due about 15 days after each monitoring period ends (read off this permit's own late-day counts in EPA's filings).

Limits in force (62)

OutfallParameterStatisticLimitMonths
001Oxygen, dissolved [DO]DAILY MN >= 7 mg/L all year
001BOD, 5-day, 20 deg. CWKLY AVG <= 10 mg/L Jan, Feb, Mar, Apr, Nov, Dec
001BOD, 5-day, 20 deg. CWKLY AVG <= 5 mg/L May, Jun, Jul, Aug, Sep, Oct
001BOD, 5-day, 20 deg. CMO AVG <= 10 mg/L Jan, Feb, Mar, Apr, Nov, Dec
001BOD, 5-day, 20 deg. CMO AVG <= 5 mg/L May, Jun, Jul, Aug, Sep, Oct
001BOD, 5-day, 20 deg. CDAILY MX report only May, Jun, Jul, Aug, Sep, Oct
001pHDAILY MN >= 6 SU all year
001pHDAILY MX <= 9 SU all year
001Solids, total suspendedDAILY MN report only Apr, Jun, Nov
001Solids, total suspendedMO AVG <= 10 mg/L Sep
001Solids, total suspendedMO AVG <= 10 mg/L Aug
001Solids, total suspendedMO AVG <= 10 mg/L Jul
001Solids, total suspendedMO AVG <= 10 mg/L Feb
001Solids, total suspendedMO AVG <= 10 mg/L Jan, Mar, May, Oct, Dec
001Solids, total suspendedMO AVG <= 10 mg/L Apr, Jun, Nov
001Solids, total suspendedDAILY MX report only Apr, Jun, Nov
001Solids, total suspendedMO AVG <= 191 lb/d Sep
001Solids, total suspendedMO AVG <= 191 lb/d Aug
001Solids, total suspendedMO AVG <= 228 lb/d Jul
001Solids, total suspendedMO AVG <= 277 lb/d Feb
001Solids, total suspendedMO AVG <= 250 lb/d Jan, Mar, May, Oct, Dec
001Solids, total suspendedMO AVG <= 259 lb/d Apr, Jun, Nov
001Solids, total suspendedWKLY AVG <= 253 lb/d Sep
001Solids, total suspendedWKLY AVG <= 252 lb/d Aug
001Solids, total suspendedWKLY AVG <= 301 lb/d Jul
001Solids, total suspendedWKLY AVG <= 366 lb/d Feb
001Solids, total suspendedWKLY AVG <= 330 lb/d Jan, Mar, May, Oct, Dec
001Solids, total suspendedWKLY AVG <= 342 lb/d Apr, Jun, Nov
001Nitrogen, total [as N]QB report only all year
001Nitrogen, ammonia total [as N]WKLY AVG <= 2.8 mg/L May, Jun, Jul, Aug, Sep
001Nitrogen, ammonia total [as N]WKLY AVG <= 6.6 mg/L Apr
001Nitrogen, ammonia total [as N]WKLY AVG <= 11 mg/L Jan, Feb, Mar, Oct, Nov, Dec
001Nitrogen, ammonia total [as N]MO AVG <= 1.1 mg/L May, Jun, Jul, Aug, Sep
001Nitrogen, ammonia total [as N]MO AVG <= 2.8 mg/L Apr
001Nitrogen, ammonia total [as N]MO AVG <= 4.5 mg/L Jan, Feb, Mar, Oct, Nov, Dec
001Nitrogen, ammonia total [as N]DAILY MX report only May, Jun, Jul, Aug, Sep
001Nitrogen, ammonia total [as N]DAILY MX report only Apr
001Nitrogen, ammonia total [as N]DAILY MX report only Jan, Feb, Mar, Oct, Nov, Dec
001Nitrogen, Kjeldahl, total [as N]QB report only all year
001Nitrite + Nitrate total [as N]QB report only all year
001Phosphorus, total [as P]6D <= .075 mg/L all year
001Phosphorus, total [as P]MO AVG <= .225 mg/L all year
001Phosphorus, total [as P]DAILY MX report only all year
001Phosphorus, total [as P]MO AVG report only all year
001Phosphorus, total [as P]DAILY MX report only all year
001Chloride [as Cl]WKLY AVG <= 500 mg/L all year
001Chloride [as Cl]MO AVG report only all year
001Chloride [as Cl]DAILY MX report only all year
001Chloride [as Cl]WKLY AVG <= 14500 lb/d all year
001Chloride [as Cl]DAILY MX report only all year
001Flow, in conduit or thru treatment plantMO AVG report only all year
001Flow, in conduit or thru treatment plantDAILY MX report only all year
001Mercury, total recoverableQB report only all year
001Coliform, fecal generalWK GEOMN <= 780 #/100mL May, Jun, Jul, Aug, Sep
001Coliform, fecal generalGEO MEAN <= 400 #/100mL May, Jun, Jul, Aug, Sep
701BOD, 5-day, 20 deg. CMO AVG report only all year
701BOD, 5-day, 20 deg. CDAILY MX report only all year
701Solids, total suspendedMO AVG report only all year
701Solids, total suspendedDAILY MX report only all year
701Flow, in conduit or thru treatment plantMO AVG report only all year
701Flow, in conduit or thru treatment plantDAILY MX report only all year
701Mercury, total recoverableQB report only all year

Built from EPA's ECHO bulk files. EPA's file, not the permit document, is the source: read your permit. Check a report before you file it · All states