City of Mason

NPDES permit OH0020494 · Major POTW · expired, expires 2026-05-31 · 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.

This permit expired on 2026-05-31 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
0required values missing, on 0 form(s)
0of 74 forms filed late

Last period with anything received: 2026-07-31.

Reporting

Reports are due about 20 days after each monitoring period ends (the most common figure among OH permits in EPA's filings — check your permit).

Limits in force (228)

OutfallParameterStatisticLimitMonths
001Temperature, water deg. centigradeMO AVG report only all year
001Temperature, water deg. centigradeDAILY MX report only all year
001Oxygen, dissolved [DO]DAILY MN >= 5.5 mg/L all year
001Solids, total suspendedMO AVG <= 12 mg/L all year
001Solids, total suspendedWKLY MAX <= 18 mg/L all year
001Solids, total suspendedMO AVG <= 591 kg/d all year
001Solids, total suspendedWKLY MAX <= 886 kg/d all year
001Oil and grease, hexane extr methodDAILY MX <= 10 mg/L all year
001Nitrogen, ammonia total [as N]MO AVG <= .45 mg/L May, Jun, Jul, Aug, Sep, Oct
001Nitrogen, ammonia total [as N]MO AVG <= 1.3 mg/L Jan, Feb, Mar, Apr, Nov, Dec
001Nitrogen, ammonia total [as N]WKLY MAX <= .6 mg/L May, Jun, Jul, Aug, Sep, Oct
001Nitrogen, ammonia total [as N]WKLY MAX <= 2 mg/L Jan, Feb, Mar, Apr, Nov, Dec
001Nitrogen, ammonia total [as N]MO AVG <= 22.2 kg/d May, Jun, Jul, Aug, Sep, Oct
001Nitrogen, ammonia total [as N]MO AVG <= 64 kg/d Jan, Feb, Mar, Apr, Nov, Dec
001Nitrogen, ammonia total [as N]WKLY MAX <= 29.6 kg/d May, Jun, Jul, Aug, Sep, Oct
001Nitrogen, ammonia total [as N]WKLY MAX <= 98.5 kg/d Jan, Feb, Mar, Apr, Nov, Dec
001Nitrogen, Kjeldahl, total [as N]MO AVG report only all year
001Nitrogen, Kjeldahl, total [as N]DAILY MX report only all year
001Nitrite + Nitrate total [as N]MO AVG report only all year
001Nitrite + Nitrate total [as N]DAILY MX report only all year
001Phosphorus, total [as P]MO AVG <= 1 mg/L May, Jun, Jul, Aug, Sep, Oct
001Phosphorus, total [as P]MO AVG report only Jan, Feb, Mar, Apr, Nov, Dec
001Phosphorus, total [as P]WKLY MAX <= 1.5 mg/L May, Jun, Jul, Aug, Sep, Oct
001Phosphorus, total [as P]DAILY MX report only Jan, Feb, Mar, Apr, Nov, Dec
001Phosphorus, total [as P]MO AVG <= 49.3 kg/d May, Jun, Jul, Aug, Sep, Oct
001Phosphorus, total [as P]WKLY MAX <= 73.9 kg/d May, Jun, Jul, Aug, Sep, Oct
001Phosphate, ortho, dissolved [as P]MO AVG report only all year
001Phosphate, ortho, dissolved [as P]DAILY MX report only all year
001Selenium, total recoverableMO AVG report only all year
001Selenium, total recoverableDAILY MX report only all year
001Barium, total recoverableMO AVG report only Mar, Jun, Aug, Dec
001Barium, total recoverableDAILY MX report only Mar, Jun, Aug, Dec
001Nickel, total recoverableMO AVG report only Mar, Jun, Aug, Dec
001Nickel, total recoverableDAILY MX report only Mar, Jun, Aug, Dec
001Silver total recoverableMO AVG report only Mar, Jun, Aug, Dec
001Silver total recoverableDAILY MX report only Mar, Jun, Aug, Dec
001Zinc, total recoverableMO AVG report only Mar, Jun, Aug, Dec
001Zinc, total recoverableDAILY MX report only Mar, Jun, Aug, Dec
001Cadmium, total recoverableMO AVG report only Mar, Jun, Aug, Dec
001Cadmium, total recoverableDAILY MX report only Mar, Jun, Aug, Dec
001Lead, total recoverableMO AVG report only Mar, Jun, Aug, Dec
001Lead, total recoverableDAILY MX report only Mar, Jun, Aug, Dec
001Chromium, total recoverableMO AVG report only Mar, Jun, Aug, Dec
001Chromium, total recoverableDAILY MX report only Mar, Jun, Aug, Dec
001Copper, total recoverableMO AVG report only all year
001Copper, total recoverableDAILY MX report only all year
001Chromium, hexavalent dissolved [as Cr]MO AVG report only Mar, Jun, Aug, Dec
001Chromium, hexavalent dissolved [as Cr]DAILY MX report only Mar, Jun, Aug, Dec
001E. coli, MTEC-MFMO GEOMN <= 126 MPN/100mL May, Jun, Jul, Aug, Sep, Oct
001E. coli, MTEC-MFWK GEOMN <= 284 MPN/100mL May, Jun, Jul, Aug, Sep, Oct
001Di[2-ethylhexyl] phthalate [DEHP]MO AVG report only Mar, Jun, Aug, Dec
001Di[2-ethylhexyl] phthalate [DEHP]DAILY MX report only Mar, Jun, Aug, Dec
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 low levelMO AVG report only all year
001Mercury, total low levelDAILY MX report only all year
001Cyanide, free availableMO AVG report only all year
001Cyanide, free availableDAILY MX report only all year
001Toxicity [acute], Ceriodaphnia dubiaMO AVG report only Sep
001Toxicity [acute], Ceriodaphnia dubiaDAILY MX report only Sep
001Toxicity [chronic], Ceriodaphnia dubiaMO AVG report only Sep
001Toxicity [chronic], Ceriodaphnia dubiaDAILY MX report only Sep
001Toxicity [acute], Pimephales promelas [Fathead Minnow]MO AVG report only Sep
001Toxicity [acute], Pimephales promelas [Fathead Minnow]DAILY MX report only Sep
001Toxicity [chronic], Pimephales promelas [Fathead Minnow]MO AVG report only Sep
001Toxicity [chronic], Pimephales promelas [Fathead Minnow]DAILY MX report only Sep
001pH, maximumDAILY MX <= 9 SU all year
001pH, minimumDAILY MN >= 6.5 SU all year
001Solids, total dissolved- 180 deg. CMO AVG report only all year
001Solids, total dissolved- 180 deg. CDAILY MX report only all year
001BOD, carbonaceous [5 day, 20 C]MO AVG <= 8 mg/L all year
001BOD, carbonaceous [5 day, 20 C]WKLY MAX <= 12 mg/L all year
001BOD, carbonaceous [5 day, 20 C]MO AVG <= 394 kg/d all year
001BOD, carbonaceous [5 day, 20 C]WKLY MAX <= 591 kg/d all year
002pHDAILY MN report only all year
002pHDAILY MX report only all year
002Solids, total suspendedMO AVG report only all year
002Oil and grease, hexane extr methodDAILY MX report only all year
002Nitrogen, inorganic totalMO AVG report only all year
002Fluoride, total [as F]DAILY MX <= 1 mg/L Sep
002Arsenic, total [as As]DAILY MX <= 100 ug/L Sep
002Beryllium, total [as Be]DAILY MX <= 100 ug/L Sep
002Boron, total [as B]DAILY MX <= 750 ug/L Sep
002Cadmium, total [as Cd]DAILY MX <= 10 ug/L Sep
002Chromium, total [as Cr]DAILY MX <= 100 ug/L Sep
002Cobalt, total [as Co]DAILY MX <= 50 ug/L Sep
002Copper, total [as Cu]DAILY MX <= 200 ug/L Sep
002Iron, total [as Fe]DAILY MX <= 5000 ug/L Sep
002Lead, total [as Pb]DAILY MX <= 1500 ug/L Sep
002Manganese, total [as Mn]DAILY MX <= 200 ug/L Sep
002Molybdenum, total [as Mo]DAILY MX <= 20000 ug/L Sep
002Nickel, total [as Ni]DAILY MX <= 200 ug/L Sep
002Vanadium, total [as V]DAILY MX <= 100 ug/L Sep
002Zinc, total [as Zn]DAILY MX <= 2000 ug/L Sep
002Aluminum, total [as Al]DAILY MX <= 5000 ug/L Sep
002Lithium, total [as Li]DAILY MX <= 2500 ug/L Sep
002Selenium, total [as Se]DAILY MX <= 20 ug/L Sep
002E. coli, MTEC-MFDAILY MX report only all year
002Flow, in conduit or thru treatment plantMO AVG report only all year
002Flow, in conduit or thru treatment plantDAILY MX report only all year
002Chlorine, total residualDAILY MN report only all year
002Chlorine, total residualDAILY MX report only all year
002BOD, carbonaceous [5 day, 20 C]MO AVG report only all year
300OverflowsMO AVG report only all year
300OverflowsDAILY MX report only all year
581Nitrogen, ammonia in bottom depositsMO AVG report only Mar, Jun, Sep, Dec
581Nitrogen, ammonia in bottom depositsDAILY MX report only Mar, Jun, Sep, Dec
581Nitrogen, Kjeldahl, total [as N]MO AVG report only Mar, Jun, Sep, Dec
581Nitrogen, Kjeldahl, total [as N]DAILY MX report only Mar, Jun, Sep, Dec
581Phosphorous, total, in bottom depositsMO AVG report only Mar, Jun, Sep, Dec
581Phosphorous, total, in bottom depositsDAILY MX report only Mar, Jun, Sep, Dec
581Potassium, in bottom depositsMO AVG report only Mar, Jun, Sep, Dec
581Potassium, in bottom depositsDAILY MX report only Mar, Jun, Sep, Dec
581Arsenic, dry weightDAILY MX <= 75 mg/kg Mar, Jun, Sep, Dec
581Cadmium, in bottom deposits [dry wgt]DAILY MX <= 85 mg/kg Mar, Jun, Sep, Dec
581Copper in bottom deposits [dry wgt]DAILY MX <= 4300 mg/kg Mar, Jun, Sep, Dec
581Lead, total dry weight [as Pb]DAILY MX <= 840 mg/kg Mar, Jun, Sep, Dec
581Nickel, tot in bottom deposits [dry wgt]DAILY MX <= 420 mg/kg Mar, Jun, Sep, Dec
581Zinc in bottom deposits [dry wgt]DAILY MX <= 7500 mg/kg Mar, Jun, Sep, Dec
581Selenium, dry weightDAILY MX <= 100 mg/kg Mar, Jun, Sep, Dec
581Biosolids weight indluding admixturesMO AVG report only Mar, Jun, Sep, Dec
581Biosolids weight indluding admixturesDAILY MX report only Mar, Jun, Sep, Dec
581Fecal coliform in sludge, CFU/gramDAILY MX <= 2000000 CFU/g Mar, Jun, Sep, Dec
581Sludge weight, dryMO AVG report only Mar, Jun, Sep, Dec
581Sludge weight, dryDAILY MX report only Mar, Jun, Sep, Dec
581Mercury, tot in bot deposits [dry wgt]DAILY MX <= 57 mg/kg Mar, Jun, Sep, Dec
581Molybdenum, sludge, total, dry weight [as Mo]DAILY MX <= 75 mg/kg Mar, Jun, Sep, Dec
584Nitrogen, ammonia in bottom depositsMO AVG report only Mar, Jun, Sep, Dec
584Nitrogen, ammonia in bottom depositsDAILY MX report only Mar, Jun, Sep, Dec
584Nitrogen, Kjeldahl, total [as N]MO AVG report only Mar, Jun, Sep, Dec
584Nitrogen, Kjeldahl, total [as N]DAILY MX report only Mar, Jun, Sep, Dec
584Phosphorous, total, in bottom depositsMO AVG report only Mar, Jun, Sep, Dec
584Phosphorous, total, in bottom depositsDAILY MX report only Mar, Jun, Sep, Dec
584Potassium, in bottom depositsMO AVG report only Mar, Jun, Sep, Dec
584Potassium, in bottom depositsDAILY MX report only Mar, Jun, Sep, Dec
584Arsenic, dry weightMO AVG <= 41 mg/kg Mar, Jun, Sep, Dec
584Arsenic, dry weightDAILY MX <= 75 mg/kg Mar, Jun, Sep, Dec
584Cadmium, in bottom deposits [dry wgt]MO AVG <= 39 mg/kg Mar, Jun, Sep, Dec
584Cadmium, in bottom deposits [dry wgt]DAILY MX <= 85 mg/kg Mar, Jun, Sep, Dec
584Copper in bottom deposits [dry wgt]MO AVG <= 1500 mg/kg Mar, Jun, Sep, Dec
584Copper in bottom deposits [dry wgt]DAILY MX <= 4300 mg/kg Mar, Jun, Sep, Dec
584Lead, total dry weight [as Pb]MO AVG <= 300 mg/kg Mar, Jun, Sep, Dec
584Lead, total dry weight [as Pb]DAILY MX <= 840 mg/kg Mar, Jun, Sep, Dec
584Nickel, tot in bottom deposits [dry wgt]MO AVG <= 420 mg/kg Mar, Jun, Sep, Dec
584Nickel, tot in bottom deposits [dry wgt]DAILY MX <= 420 mg/kg Mar, Jun, Sep, Dec
584Zinc in bottom deposits [dry wgt]MO AVG <= 2800 mg/kg Mar, Jun, Sep, Dec
584Zinc in bottom deposits [dry wgt]DAILY MX <= 7500 mg/kg Mar, Jun, Sep, Dec
584Selenium, dry weightMO AVG <= 100 mg/kg Mar, Jun, Sep, Dec
584Selenium, dry weightDAILY MX <= 100 mg/kg Mar, Jun, Sep, Dec
584Fecal coliformDAILY MX <= 1000 MPN/g Mar, Jun, Sep, Dec
584Biosolids weight indluding admixturesMO AVG report only Mar, Jun, Sep, Dec
584Biosolids weight indluding admixturesDAILY MX report only Mar, Jun, Sep, Dec
584Sludge weight, dryMO AVG report only Mar, Jun, Sep, Dec
584Sludge weight, dryDAILY MX report only Mar, Jun, Sep, Dec
584Mercury, tot in bot deposits [dry wgt]MO AVG <= 17 mg/kg Mar, Jun, Sep, Dec
584Mercury, tot in bot deposits [dry wgt]DAILY MX <= 57 mg/kg Mar, Jun, Sep, Dec
584Molybdenum, sludge, total, dry weight [as Mo]MO AVG <= 75 mg/kg Mar, Jun, Sep, Dec
584Molybdenum, sludge, total, dry weight [as Mo]DAILY MX <= 75 mg/kg Mar, Jun, Sep, Dec
601Solids, total suspendedMO AVG report only all year
601Solids, total suspendedDAILY MX report only all year
601Cyanide, total [as CN]MO AVG report only Mar, Jun, Aug, Dec
601Cyanide, total [as CN]DAILY MX report only Mar, Jun, Aug, Dec
601Selenium, total recoverableMO AVG report only all year
601Selenium, total recoverableDAILY MX report only all year
601Barium, total recoverableMO AVG report only Mar, Jun, Aug, Dec
601Barium, total recoverableDAILY MX report only Mar, Jun, Aug, Dec
601Nickel, total recoverableMO AVG report only Mar, Jun, Aug, Dec
601Nickel, total recoverableDAILY MX report only Mar, Jun, Aug, Dec
601Silver total recoverableMO AVG report only Mar, Jun, Aug, Dec
601Silver total recoverableDAILY MX report only Mar, Jun, Aug, Dec
601Zinc, total recoverableMO AVG report only Mar, Jun, Aug, Dec
601Zinc, total recoverableDAILY MX report only Mar, Jun, Aug, Dec
601Cadmium, total recoverableMO AVG report only Mar, Jun, Aug, Dec
601Cadmium, total recoverableDAILY MX report only Mar, Jun, Aug, Dec
601Lead, total recoverableMO AVG report only Mar, Jun, Aug, Dec
601Lead, total recoverableDAILY MX report only Mar, Jun, Aug, Dec
601Chromium, total recoverableMO AVG report only Mar, Jun, Aug, Dec
601Chromium, total recoverableDAILY MX report only Mar, Jun, Aug, Dec
601Copper, total recoverableMO AVG report only all year
601Copper, total recoverableDAILY MX report only all year
601Chromium, hexavalent dissolved [as Cr]MO AVG report only Mar, Jun, Aug, Dec
601Chromium, hexavalent dissolved [as Cr]DAILY MX report only Mar, Jun, Aug, Dec
601Mercury, total low levelMO AVG report only all year
601Mercury, total low levelDAILY MX report only all year
601pH, maximumDAILY MX report only all year
601pH, minimumDAILY MN report only all year
601BOD, carbonaceous [5 day, 20 C]MO AVG report only all year
601BOD, carbonaceous [5 day, 20 C]DAILY MX report only all year
801Temperature, water deg. centigradeMO AVG report only all year
801Temperature, water deg. centigradeDAILY MX report only all year
801Oxygen, dissolved [DO]DAILY MN report only all year
801pHDAILY MN report only all year
801pHDAILY MX report only all year
801Nitrogen, ammonia total [as N]MO AVG report only all year
801Nitrogen, ammonia total [as N]DAILY MX report only all year
801Nitrogen, Kjeldahl, total [as N]MO AVG report only all year
801Nitrogen, Kjeldahl, total [as N]DAILY MX report only all year
801Nitrite + Nitrate total [as N]MO AVG report only all year
801Nitrite + Nitrate total [as N]DAILY MX report only all year
801Phosphorus, total [as P]MO AVG report only all year
801Phosphorus, total [as P]DAILY MX report only all year
801E. coli, MTEC-MFMO GEOMN report only Jun, Jul, Aug
801E. coli, MTEC-MFDAILY MX report only Jun, Jul, Aug
801%Effect Static Renewal 48Hr Acute Ceriodaphnia dubiaMO AVG report only Sep
801%Effect Static Renewal 48Hr Acute Ceriodaphnia dubiaDAILY MX report only Sep
801%Effect Static Renewal 96Hr Acute Pimephales promelasMO AVG report only Sep
801%Effect Static Renewal 96Hr Acute Pimephales promelasDAILY MX report only Sep
801%Effect Static Renewal 7 Day Chronic Ceriodaphnia dubiaMO AVG report only Sep
801%Effect Static Renewal 7 Day Chronic Ceriodaphnia dubiaDAILY MX report only Sep
801%Effect Static Renewal 7Day Chronic Pimephales promelasMO AVG report only Sep
801%Effect Static Renewal 7Day Chronic Pimephales promelasDAILY MX report only Sep
901Temperature, water deg. centigradeMO AVG report only all year
901Temperature, water deg. centigradeDAILY MX report only all year
901Oxygen, dissolved [DO]DAILY MN report only all year
901pHDAILY MN report only all year
901pHDAILY MX report only all year
901Nitrogen, ammonia total [as N]MO AVG report only all year
901Nitrogen, ammonia total [as N]DAILY MX report only all year
901Nitrogen, Kjeldahl, total [as N]MO AVG report only all year
901Nitrogen, Kjeldahl, total [as N]DAILY MX report only all year
901Nitrite + Nitrate total [as N]MO AVG report only all year
901Nitrite + Nitrate total [as N]DAILY MX report only all year
901Phosphorus, total [as P]MO AVG report only all year
901Phosphorus, total [as P]DAILY MX report only all year
901Hardness, total [as CaCO3]MO AVG report only all year
901Hardness, total [as CaCO3]DAILY MX report only all year
901E. coli, MTEC-MFMO GEOMN report only Jun, Jul, Aug
901E. coli, MTEC-MFDAILY MX report only Jun, Jul, Aug

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