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Danbury WPCF

Sewage treatment plant, major discharger, Danbury, Connecticut. NPDES permit CT0100145 expired Jun 30, 2026; its limits still apply. Last 12 months: over a limit once (last October 2025), 1 of 12 reports late. Source: EPA ECHO, Oct 22, 2026.

Reports due
About 15 days after each period: form 1 monthly (49 values)
Last report on file
September 2026
Oct 2024 – Sep 2025
1 value over a limit, 0 required values missing, 0 of 12 reports late

Last 12 months (Oct 1, 2025 – Sep 30, 2026)

Period endingParameterReportedLimitOver by
October 2025Copper, total [as Cu], monthly average.021 mg/L≤ .019 mg/L11%

Limits in force (86)

ParameterStatisticLimitMonths
Flow ratemonthly averagereport only (MGD)all year
Flow ratedaily maximumreport only (MGD)all year
Oxygen, dissolved [DO]instantaneous minimum≥ 6 mg/Lall year
BOD, 5-day, 20 deg. Cmonthly average≤ 30 mg/LJan, Feb, Mar, Apr, May, Jun, Oct, Nov, Dec
BOD, 5-day, 20 deg. Cmonthly average≤ 20 mg/LJul–Sep
BOD, 5-day, 20 deg. Cdaily maximum≤ 50 mg/LJan, Feb, Mar, Apr, May, Jun, Oct, Nov, Dec
BOD, 5-day, 20 deg. Cdaily maximum≤ 30 mg/LJul–Sep
BOD, 5-day, 20 deg. Cmonthly averagereport only (mg/L)all year
BOD, 5-day, 20 deg. Cdaily maximumreport only (mg/L)Jan, Apr, Jul, Oct
pHinstantaneous minimum≥ 6 SUall year
pHinstantaneous maximum≤ 9 SUall year
Solids, total suspendedmonthly average≤ 30 mg/Lall year
Solids, total suspendeddaily maximum≤ 50 mg/Lall year
Solids, total suspendedmonthly averagereport only (mg/L)all year
Solids, total suspendeddaily maximumreport only (mg/L)Jan, Apr, Jul, Oct
Nitrogen, ammonia total [as N]monthly average≤ 1.9 mg/LMay, Oct
Nitrogen, ammonia total [as N]monthly average≤ 1.7 mg/LJun
Nitrogen, ammonia total [as N]monthly average≤ 1.5 mg/LJul–Sep
Nitrogen, ammonia total [as N]monthly average≤ 4 mg/LJan, Feb, Mar, Apr, Nov, Dec
Nitrogen, ammonia total [as N]daily maximumreport only (mg/L)May, Oct
Nitrogen, ammonia total [as N]daily maximumreport only (mg/L)Jun
Nitrogen, ammonia total [as N]daily maximumreport only (mg/L)Jul–Sep
Nitrogen, ammonia total [as N]daily maximumreport only (mg/L)Jan, Feb, Mar, Apr, Nov, Dec
Nitrogen, ammonia total [as N]daily maximumreport only (mg/L)Jan, Apr, Jul, Oct
Nitrogen, nitrite total [as N]daily maximumreport only (mg/L)Jan, Apr, Jul, Oct
Nitrogen, nitrate total [as N]daily maximumreport only (mg/L)Jan, Apr, Jul, Oct
Phosphorus, total [as P]monthly averagereport only (mg/L)Apr–Oct
Phosphorus, total [as P]daily maximumreport only (mg/L)Jan, Apr, Jul, Oct
Cyanide, total [as CN]daily maximumreport only (mg/L)Jan, Apr, Jul, Oct
Cyanide, free [amenable to chlorination]daily maximumreport only (mg/L)Jan, Apr, Jul, Oct
Arsenic, total [as As]daily maximumreport only (mg/L)Jan, Apr, Jul, Oct
Beryllium, total [as Be]daily maximumreport only (mg/L)Jan, Apr, Jul, Oct
Cadmium, total [as Cd]daily maximumreport only (mg/L)Jan, Apr, Jul, Oct
Chromium, hexavalent [as Cr]daily maximumreport only (mg/L)Jan, Apr, Jul, Oct
Chromium, total [as Cr]daily maximumreport only (mg/L)Jan, Apr, Jul, Oct
Copper, total [as Cu]monthly average≤ .019 mg/Lall year
Copper, total [as Cu]daily maximum≤ .029 mg/Lall year
Copper, total [as Cu]monthly averagereport only (mg/L)all year
Copper, total [as Cu]daily maximumreport only (mg/L)all year
Copper, total [as Cu]daily maximumreport only (mg/L)Jan, Apr, Jul, Oct
Iron, total [as Fe]daily maximumreport only (mg/L)Jan, Apr, Jul, Oct
Lead, total [as Pb]monthly averagereport only (mg/L)all year
Lead, total [as Pb]daily maximumreport only (mg/L)all year
Lead, total [as Pb]monthly average≤ .052 kg/dall year
Lead, total [as Pb]daily maximum≤ .105 kg/dall year
Lead, total [as Pb]monthly averagereport only (kg/d)all year
Lead, total [as Pb]daily maximumreport only (kg/d)all year
Lead, total [as Pb]daily maximumreport only (mg/L)Jan, Apr, Jul, Oct
Thallium, total [as Tl]daily maximumreport only (mg/L)Jan, Apr, Jul, Oct
Nickel, total [as Ni]daily maximumreport only (mg/L)Jan, Apr, Jul, Oct
Silver, total [as Ag]daily maximumreport only (mg/L)Jan, Apr, Jul, Oct
Zinc, total [as Zn]monthly average≤ .053 mg/Lall year
Zinc, total [as Zn]daily maximum≤ .08 mg/Lall year
Zinc, total [as Zn]monthly averagereport only (mg/L)all year
Zinc, total [as Zn]daily maximumreport only (mg/L)all year
Zinc, total [as Zn]daily maximumreport only (mg/L)Jan, Apr, Jul, Oct
Antimony, total [as Sb]daily minimumreport only (mg/L)Jan, Apr, Jul, Oct
Aluminum, total recoverabledaily maximumreport only (mg/L)Jan, Apr, Jul, Oct
Aluminum, total [as Al]daily maximumreport only (mg/L)Jan, Apr, Jul, Oct
Polychlorinated biphenyls [PCBs]instantaneous maximumreport only (mg/kg)Jan, Mar, May, Jul, Sep, Nov
Phenolsdaily maximumreport only (mg/L)Jan, Apr, Jul, Oct
Chlorine, total residualinstantaneous minimum≥ .01 mg/LMay–Sep
Chlorine, total residualinstantaneous maximum≤ .02 mg/LMay–Sep
Chlorine, total residualdaily maximumreport only (mg/L)Jan, Apr, Jul, Oct
E. coli30-day geometric mean≤ 126 #/100mLMay–Sep
E. colimaximum≤ 410 #/100mLMay–Sep
Phosphorus, Total [Avg Seasonal Load Cap]monthly average≤ 7.55 lb/dOct
Arsenic, sludge tot. dry wt [as As]instantaneous maximumreport only (mg/kg)Jan, Mar, May, Jul, Sep, Nov
Beryllium, sludge, tot. dry wt [as Be]instantaneous maximumreport only (mg/kg)Jan, Mar, May, Jul, Sep, Nov
Solids, total, percentinstantaneous minimumreport only (%)Jan, Mar, May, Jul, Sep, Nov
Solids, fixed, % of total solidsinstantaneous minimumreport only (%)Jan, Mar, May, Jul, Sep, Nov
Solids, volatile % of total solidsinstantaneous minimumreport only (%)Jan, Mar, May, Jul, Sep, Nov
Mercury, total [as Hg]daily maximumreport only (mg/L)Jan, Apr, Jul, Oct
Zinc, sludge, total, dry weight [as Zn]instantaneous maximumreport only (mg/kg)Jan, Mar, May, Jul, Sep, Nov
Lead, sludge, total, dry weight [as Pb]instantaneous maximumreport only (mg/kg)Jan, Mar, May, Jul, Sep, Nov
Nickel, sludge, total, dry weight [as Ni]instantaneous maximumreport only (mg/kg)Jan, Mar, May, Jul, Sep, Nov
Mercury, sludge, total, dry weight [as Hg]instantaneous maximumreport only (mg/kg)Jan, Mar, May, Jul, Sep, Nov
Chromium, sludge, total, dry weight [as Cr]instantaneous maximumreport only (mg/kg)Jan, Mar, May, Jul, Sep, Nov
Copper, sludge, total, dry weight [as Cu]instantaneous maximumreport only (mg/kg)Jan, Mar, May, Jul, Sep, Nov
Cadmium, sludge, total, dry weight [as Cd]instantaneous maximumreport only (mg/kg)Jan, Mar, May, Jul, Sep, Nov
BOD, carbonaceous [5 day, 5 C]monthly averagereport only (mg/L)all year
BOD, carbonaceous [5 day, 5 C]daily maximumreport only (mg/L)all year
BOD, 5-day, percent removalminimum % removal≥ 85 %all year
Solids, suspended percent removalminimum % removal≥ 85 %all year
NOAEL Static 48Hr Acute D. pulexminimum≥ 90 % survivalJan, Apr, Jul, Oct
NOAEL Static 48Hr Acute Pimephales promelasminimum≥ 90 % survivalJan, Apr, Jul, Oct

How strict are these limits?

Cited limits by parameter: Connecticut's rules and the federal ones.

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On EPA ECHO: Facility report · DMR history

Your permit document is the final word. As JSON: /api/v1/permits/CT0100145 · MCP: https://passage-data.com/mcp