SD GFP - Sylvan Lake (Custer State Park)

NPDES permit SD0024279 · Minor POTW · effective, expires 2031-05-31 · 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.

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

0values over a limit
0required values missing, on 0 form(s)
0of 33 forms filed late

Last period with anything received: 2026-08-31.

Reporting

Reports are due about 28 days after each monitoring period ends (the most common figure among SD permits in EPA's filings — check your permit).

Limits in force (47)

OutfallParameterStatisticLimitMonths
002Temperature, water deg. fahrenheit30DA AVG report only all year
002Temperature, water deg. fahrenheitDAILY MX report only all year
002Flow rate30DA AVG report only all year
002Flow rateDAILY MX report only all year
002BOD, 5-day, 20 deg. C30DA AVG <= 10 mg/L all year
002BOD, 5-day, 20 deg. CDAILY MX <= 17.5 mg/L all year
002pHDAILY MN >= 6.5 SU all year
002pHDAILY MX <= 8.8 SU all year
002Solids, total suspended30DA AVG <= 10 mg/L all year
002Solids, total suspendedDAILY MX <= 17.5 mg/L all year
002Nitrogen, total [as N]DAILY MX report only all year
002Nitrogen, ammonia total [as N]30DA AVG <= 1 mg/L Jun, Jul, Aug, Sep
002Nitrogen, ammonia total [as N]30DA AVG <= 1.1 mg/L May
002Nitrogen, ammonia total [as N]30DA AVG <= 3.7 mg/L Feb, Mar
002Nitrogen, ammonia total [as N]30DA AVG <= 3.7 mg/L Apr
002Nitrogen, ammonia total [as N]30DA AVG <= 1.3 mg/L Oct
002Nitrogen, ammonia total [as N]30DA AVG <= 3.6 mg/L Jan, Nov, Dec
002Nitrogen, ammonia total [as N]DAILY MX <= 1.1 mg/L Jun, Jul, Aug, Sep
002Nitrogen, ammonia total [as N]DAILY MX <= 5.1 mg/L May
002Nitrogen, ammonia total [as N]DAILY MX <= 8.3 mg/L Feb, Mar
002Nitrogen, ammonia total [as N]DAILY MX <= 11.3 mg/L Apr
002Nitrogen, ammonia total [as N]DAILY MX <= 2.3 mg/L Oct
002Nitrogen, ammonia total [as N]DAILY MX <= 8.3 mg/L Jan, Nov, Dec
002Phosphorus, total [as P]DAILY MX report only all year
002Chlorine, total residualDAILY MX <= .019 mg/L all year
002E. coli, colony forming units [CFU]30DA GEO <= 126 #/100mL May, Jun, Jul, Aug, Sep
002E. coli, colony forming units [CFU]DAILY MX <= 235 #/100mL May, Jun, Jul, Aug, Sep
002Flow, totalMO TOTAL report only all year
002Duration of dischargeMO TOTAL report only all year
003Temperature, water deg. fahrenheit30DA AVG report only all year
003Temperature, water deg. fahrenheitDAILY MX report only all year
003Flow rate30DA AVG report only all year
003Flow rateDAILY MX report only all year
003pHDAILY MN >= 6 SU all year
003pHDAILY MX <= 8.8 SU all year
003Nitrogen, ammonia total [as N]30DA AVG <= 1 mg/L Jun, Jul, Aug, Sep
003Nitrogen, ammonia total [as N]30DA AVG <= 1.1 mg/L May
003Nitrogen, ammonia total [as N]30DA AVG <= 3.7 mg/L Feb, Mar
003Nitrogen, ammonia total [as N]30DA AVG <= 3.7 mg/L Apr
003Nitrogen, ammonia total [as N]30DA AVG <= 1.3 mg/L Oct
003Nitrogen, ammonia total [as N]30DA AVG <= 3.6 mg/L Jan, Nov, Dec
003Nitrogen, ammonia total [as N]DAILY MX <= 1.1 mg/L Jun, Jul, Aug, Sep
003Nitrogen, ammonia total [as N]DAILY MX <= 5.1 mg/L May
003Nitrogen, ammonia total [as N]DAILY MX <= 8.3 mg/L Feb, Mar
003Nitrogen, ammonia total [as N]DAILY MX <= 11.3 mg/L Apr
003Nitrogen, ammonia total [as N]DAILY MX <= 2.3 mg/L Oct
003Nitrogen, ammonia total [as N]DAILY MX <= 8.3 mg/L Jan, Nov, Dec

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