North San Mateo County Sanitation District

NPDES permit CA0037737 · Major POTW · effective, expires 2028-01-31 · 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 9 forms filed late

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

Reporting

Reports are due about 32 days after each monitoring period ends (the most common figure among CA permits in EPA's filings — check your permit).

Limits in force (196)

OutfallParameterStatisticLimitMonths
001RadioactivityDAILY MX report only all year
001RadioactivityDAILY MX report only all year
001pHMINIMUM >= 6 SU all year
001pHMAXIMUM <= 9 SU all year
001Solids, total suspendedMO AVG <= 30 mg/L all year
001Solids, total suspendedWKLY AVG <= 45 mg/L all year
001Nitrogen, ammonia total [as N]6A <= 70 mg/L all year
001Nitrogen, ammonia total [as N]DAILY MX <= 280 mg/L all year
001Nitrogen, ammonia total [as N]INST MAX <= 700 mg/L all year
001Nitrogen, ammonia total [as N]DAILY MX report only all year
001Nitrogen, ammonia total [as N]DAILY MX report only all year
001Nitrogen, ammonia total [as N]6A <= 1900 kg/d all year
001Nitrogen, ammonia total [as N]DAILY MX <= 9200 kg/d all year
001Cyanide, total [as CN]DAILY MX report only all year
001Cyanide, total [as CN]DAILY MX report only all year
001Arsenic, total recoverableDAILY MX report only all year
001Arsenic, total recoverableDAILY MX report only all year
001Selenium, total recoverableDAILY MX report only all year
001Selenium, total recoverableDAILY MX report only all year
001Thallium, total recoverableDAILY MX report only all year
001Thallium, total recoverableDAILY MX report only all year
001Beryllium, total recoverable [as Be]DAILY MX report only all year
001Beryllium, total recoverable [as Be]DAILY MX report only all year
001Chromium, hexavalent [as Cr]DAILY MX report only all year
001Chromium, hexavalent [as Cr]DAILY MX report only all year
001Chromium, trivalent [as Cr]DAILY MX report only all year
001Chromium, trivalent [as Cr]DAILY MX report only all year
001Nickel, total recoverableDAILY MX report only all year
001Nickel, total recoverableDAILY MX report only all year
001Silver total recoverableDAILY MX report only all year
001Silver total recoverableDAILY MX report only all year
001Zinc, total recoverableDAILY MX report only all year
001Zinc, total recoverableDAILY MX report only all year
001Cadmium, total recoverableDAILY MX report only all year
001Cadmium, total recoverableDAILY MX report only all year
001Lead, total recoverableDAILY MX report only all year
001Lead, total recoverableDAILY MX report only all year
001Chromium, total recoverableDAILY MX report only all year
001Chromium, total recoverableDAILY MX report only all year
001Copper, total recoverableDAILY MX report only all year
001Copper, total recoverableDAILY MX report only all year
001Antimony, total recoverableDAILY MX report only all year
001Antimony, total recoverableDAILY MX report only all year
0012-Methyl-4,6-dinitrophenolDAILY MX report only all year
0012-Methyl-4,6-dinitrophenolDAILY MX report only all year
001TributyltinDAILY MX report only all year
001TributyltinDAILY MX report only all year
001Polynuclear Aromatic Hydrocarbons [PAHs]DAILY MX report only all year
001Polynuclear Aromatic Hydrocarbons [PAHs]DAILY MX report only all year
001DichlorobromomethaneDAILY MX report only all year
001DichlorobromomethaneDAILY MX report only all year
001Carbon tetrachlorideDAILY MX report only all year
001Carbon tetrachlorideDAILY MX report only all year
0011,2-DichloroethaneDAILY MX report only all year
0011,2-DichloroethaneDAILY MX report only all year
001DibromochloromethaneDAILY MX report only all year
001DibromochloromethaneDAILY MX report only all year
001ChloroformDAILY MX report only all year
001ChloroformDAILY MX report only all year
001TolueneDAILY MX report only all year
001TolueneDAILY MX report only all year
001BenzeneDAILY MX report only all year
001BenzeneDAILY MX report only all year
001AcroleinDAILY MX report only all year
001AcroleinDAILY MX report only all year
001AcrylonitrileDAILY MX report only all year
001AcrylonitrileDAILY MX report only all year
001Bis[2-chloroethyl] etherDAILY MX report only all year
001Bis[2-chloroethyl] etherDAILY MX report only all year
001Bis[2-chloroethoxy]methaneDAILY MX report only all year
001Bis[2-chloroethoxy]methaneDAILY MX report only all year
001Bis[2-chloroisopropyl] etherDAILY MX report only all year
001Bis[2-chloroisopropyl] etherDAILY MX report only all year
001ChlorobenzeneDAILY MX report only all year
001ChlorobenzeneDAILY MX report only all year
001Diethyl phthalateDAILY MX report only all year
001Diethyl phthalateDAILY MX report only all year
001Dimethyl phthalateDAILY MX report only all year
001Dimethyl phthalateDAILY MX report only all year
0011,2-DiphenylhydrazineDAILY MX report only all year
0011,2-DiphenylhydrazineDAILY MX report only all year
001EthylbenzeneDAILY MX report only all year
001EthylbenzeneDAILY MX report only all year
001FluorantheneDAILY MX report only all year
001FluorantheneDAILY MX report only all year
001HexachlorocyclopentadieneDAILY MX report only all year
001HexachlorocyclopentadieneDAILY MX report only all year
001HexachlorobutadieneDAILY MX report only all year
001HexachlorobutadieneDAILY MX report only all year
001HexachloroethaneDAILY MX report only all year
001HexachloroethaneDAILY MX report only all year
001IsophoroneDAILY MX report only all year
001IsophoroneDAILY MX report only all year
001Methylene chlorideDAILY MX report only all year
001Methylene chlorideDAILY MX report only all year
001N-Nitrosodi-N-propylamineDAILY MX report only all year
001N-Nitrosodi-N-propylamineDAILY MX report only all year
001N-NitrosodiphenylamineDAILY MX report only all year
001N-NitrosodiphenylamineDAILY MX report only all year
001N-Nitrosodimethylamine [NDMA]DAILY MX report only all year
001N-Nitrosodimethylamine [NDMA]DAILY MX report only all year
001NitrobenzeneDAILY MX report only all year
001NitrobenzeneDAILY MX report only all year
001TetrachloroethyleneDAILY MX report only all year
001TetrachloroethyleneDAILY MX report only all year
0011,1-DichloroethyleneDAILY MX report only all year
0011,1-DichloroethyleneDAILY MX report only all year
0011,1,1-TrichloroethaneDAILY MX report only all year
0011,1,1-TrichloroethaneDAILY MX report only all year
0011,1,2-TrichloroethaneDAILY MX report only all year
0011,1,2-TrichloroethaneDAILY MX report only all year
0011,1,2,2-TetrachloroethaneDAILY MX report only all year
0011,1,2,2-TetrachloroethaneDAILY MX report only all year
0011,4-DichlorobenzeneDAILY MX report only all year
0011,4-DichlorobenzeneDAILY MX report only all year
0012,4-DinitrotolueneDAILY MX report only all year
0012,4-DinitrotolueneDAILY MX report only all year
0012,4-DinitrophenolDAILY MX report only all year
0012,4-DinitrophenolDAILY MX report only all year
0012,4,6-TrichlorophenolDAILY MX report only all year
0012,4,6-TrichlorophenolDAILY MX report only all year
0013,3'-DichlorobenzidineDAILY MX report only all year
0013,3'-DichlorobenzidineDAILY MX report only all year
001Di[2-ethylhexyl] phthalate [DEHP]DAILY MX report only all year
001Di[2-ethylhexyl] phthalate [DEHP]DAILY MX report only all year
001Di-n-butyl phthalateDAILY MX report only all year
001Di-n-butyl phthalateDAILY MX report only all year
001BenzidineDAILY MX report only all year
001BenzidineDAILY MX report only all year
001Vinyl chlorideDAILY MX report only all year
001Vinyl chlorideDAILY MX report only all year
001TrichloroethyleneDAILY MX report only all year
001TrichloroethyleneDAILY MX report only all year
001AldrinDAILY MX report only all year
001AldrinDAILY MX report only all year
001Chlordane [tech mix. and metabolites]DAILY MX report only all year
001Chlordane [tech mix. and metabolites]DAILY MX report only all year
001DDT/DDD/DDE, sum of p,p' & o,p' isomersDAILY MX report only all year
001DDT/DDD/DDE, sum of p,p' & o,p' isomersDAILY MX report only all year
001DieldrinDAILY MX report only all year
001DieldrinDAILY MX report only all year
001Endosulfan, totalDAILY MX report only all year
001Endosulfan, totalDAILY MX report only all year
001EndrinDAILY MX report only all year
001EndrinDAILY MX report only all year
001ToxapheneDAILY MX report only all year
001ToxapheneDAILY MX report only all year
001HeptachlorDAILY MX report only all year
001HeptachlorDAILY MX report only all year
001Heptachlor epoxideDAILY MX report only all year
001Heptachlor epoxideDAILY MX report only all year
001HexachlorobenzeneDAILY MX report only all year
001HexachlorobenzeneDAILY MX report only all year
001Flow, in conduit or thru treatment plantDAILY AV report only all year
001Chlorine, total residual6A <= .14 mg/L all year
001Chlorine, total residualDAILY MX <= .57 mg/L all year
001Chlorine, total residualINST MAX <= 4.3 mg/L all year
001Chlorine, total residualDAILY MX report only all year
001Chlorine, total residualDAILY MX report only all year
001Chlorine, total residual6A <= 3.9 kg/d all year
001Chlorine, total residualDAILY MX <= 17 kg/d all year
001Flow, totalMO TOTAL report only all year
001Polychlorinated biphenyls [PCBs], sum of AroclorsDAILY MX report only all year
001Polychlorinated biphenyls [PCBs], sum of AroclorsDAILY MX report only all year
001EnterococciGEO MEAN <= 3500 MPN/100mL all year
001Enterococci9C <= 13000 MPN/100mL all year
001Mercury, total recoverableDAILY MX report only all year
001Mercury, total recoverableDAILY MX report only all year
001Phenols, chlorinatedDAILY MX report only all year
001Phenols, chlorinatedDAILY MX report only all year
0011,3-DichloropropeneDAILY MX report only all year
0011,3-DichloropropeneDAILY MX report only all year
001Hexachlorocyclohexane, totalDAILY MX report only all year
001Hexachlorocyclohexane, totalDAILY MX report only all year
001Phenolic compounds, unchlorinatedDAILY MX report only all year
001Phenolic compounds, unchlorinatedDAILY MX report only all year
001HalomethanesDAILY MX report only all year
001HalomethanesDAILY MX report only all year
001BOD, carbonaceous [5 day, 20 C]MO AVG <= 25 mg/L all year
001BOD, carbonaceous [5 day, 20 C]WKLY AVG <= 40 mg/L all year
001BOD, carb-5 day, 20 deg C, percent removalMO AV MN >= 85 % all year
001Solids, suspended percent removalMO AV MN >= 85 % all year
001DichlorobenzeneDAILY MX report only all year
001DichlorobenzeneDAILY MX report only all year
001TCDD equivalentsDAILY MX report only all year
001TCDD equivalentsDAILY MX report only all year
001Static 48Hr Chronic Mytilis SpeciesAVERAGE report only all year
001Static 48Hr Chronic Mytilis SpeciesAVERAGE report only all year
001Static 48Hr Chronic Mytilis SpeciesDAILY MX report only all year
001Static 48Hr Chronic Mytilis SpeciesDAILY MX report only all year
INFSolids, total suspendedMO AVG report only all year
INFSolids, total suspendedDAILY MX report only all year
INFFlow, in conduit or thru treatment plantDAILY AV report only all year
INFFlow, totalMO TOTAL report only all year
INFBOD, carbonaceous [5 day, 20 C]MO AVG report only all year
INFBOD, carbonaceous [5 day, 20 C]DAILY MX report only all year

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