Black Hills Corporation

NPDES permit WY0097001 · Minor NON-POTW · effective, expires 2030-10-31 · EPA's file as of 2026-09-19

Check this month's numbers before you file

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

0values over a limit
0required values missing, on 0 form(s)
0of 6 forms filed late

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

Reporting

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

Limits in force (25)

OutfallParameterStatisticLimitMonths
001pHDAILY MN >= 6.5 SU all year
001pHDAILY MX <= 9 SU all year
001Solids, total suspendedANNL AVG <= 27 mg/L all year
001Solids, total suspendedANNL AVG <= 27 mg/L all year
001Solids, total suspendedQB report only all year
001Solids, total suspendedQB report only all year
001Arsenic, dissolved [as As]DAILY MX <= 10.6 ug/L all year
001Chromium, total [as Cr]DAILY MX <= .2 mg/L all year
001Chromium, total [as Cr]MO AVG <= .2 mg/L all year
001Zinc, total [as Zn]DAILY MX <= 1 mg/L all year
001Zinc, total [as Zn]MO AVG <= 1 mg/L all year
001Selenium, total [as Se]MO AVG <= 20 ug/L all year
001Selenium, total [as Se]DAILY MX <= 5 ug/L all year
001DurationMO TOTAL report only all year
001Chlorine, total residualDAILY MX <= .0203 mg/L all year
001Chlorine, total residualMO AVG <= .0118 mg/L all year
001Chlorine, free availableDAILY MX <= .5 mg/L all year
001Chlorine, free availableMO AVG <= .2 mg/L all year
001FlowDAILY MX <= .052 MGD all year
001FlowMO AVG report only all year
001Produced water, oil and greaseDAILY MX <= 10 mg/L all year
001Pass/Fail Static 48Hr Acute Ceriodaphnia dubia4C <= 0 pass=0;fail=1 all year
001Pass/Fail Static 96 Hr Acute Pimephales Promelas9D <= 0 pass=0;fail=1 all year
001Pass/Fail Static Renewal 7 Day Chronic Ceriodaphnia dubia7E <= 0 pass=0;fail=1 all year
001Pass/Fail Static Renewal 7Day Chronic Pimephales promelas7E <= 0 pass=0;fail=1 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