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Mattabassett District Cromwell

Sewage treatment plant, major discharger, Cromwell, Connecticut. NPDES permit CT0100307 expired Jul 31, 2019; its limits still apply. Last 12 months: no values over a limit. Source: EPA ECHO, Oct 22, 2026.

Reports due
About 31 days after each period: form 1 monthly (45 values)
Last report on file
September 2026
Oct 2024 – Sep 2025
0 values over a limit, 0 required values missing, 0 of 12 reports late

Limits in force (88)

ParameterStatisticLimitMonths
Flow ratemonthly averagereport only (MGD)all year
Flow ratedaily maximumreport only (MGD)all year
BOD, 5-day, 20 deg. Cdaily maximumreport only (mg/L)Feb, May, Aug, Nov
BOD, 5-day, 20 deg. Cdaily maximumreport only (mg/L)Jan, Mar, Apr, Jun, Jul, Sep, Oct, Dec
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)Feb, May, Aug, Nov
Solids, total suspendeddaily maximumreport only (mg/L)Jan, Mar, Apr, Jun, Jul, Sep, Oct, Dec
Nitrogen, ammonia total [as N]daily maximumreport only (mg/L)Feb, May, Aug, Nov
Nitrogen, ammonia total [as N]daily maximumreport only (mg/L)Jan, Mar, Apr, Jun, Jul, Sep, Oct, Dec
Nitrogen, nitrite total [as N]daily maximumreport only (mg/L)Feb, May, Aug, Nov
Nitrogen, nitrite total [as N]daily maximumreport only (mg/L)Jan, Mar, Apr, Jun, Jul, Sep, Oct, Dec
Nitrogen, nitrate total [as N]daily maximumreport only (mg/L)Jan, Mar, Apr, Jun, Jul, Sep, Oct, Dec
Nitrogen, nitrate total [as N]daily maximumreport only (mg/L)Feb, May, Aug, Nov
Phosphorus, total [as P]daily maximumreport only (mg/L)all year
Phosphorus, total [as P]daily maximumreport only (mg/L)Feb, May, Aug, Nov
Phosphorus, total [as P]daily maximumreport only (mg/L)Jan, Mar, Apr, Jun, Jul, Sep, Oct, Dec
Cyanide, total [as CN]daily maximumreport only (mg/L)Feb, May, Aug, Nov
Cyanide, total [as CN]daily maximumreport only (mg/L)Jan, Mar, Apr, Jun, Jul, Sep, Oct, Dec
Cyanide, free [amenable to chlorination]daily maximumreport only (mg/L)Feb, May, Aug, Nov
Cyanide, free [amenable to chlorination]daily maximumreport only (mg/L)Jan, Mar, Apr, Jun, Jul, Sep, Oct, Dec
Arsenic, total [as As]daily maximumreport only (mg/L)Feb, May, Aug, Nov
Arsenic, total [as As]daily maximumreport only (mg/L)Jan, Mar, Apr, Jun, Jul, Sep, Oct, Dec
Beryllium, total [as Be]daily maximumreport only (mg/L)Feb, May, Aug, Nov
Beryllium, total [as Be]daily maximumreport only (mg/L)Jan, Mar, Apr, Jun, Jul, Sep, Oct, Dec
Cadmium, total [as Cd]daily maximumreport only (mg/L)Feb, May, Aug, Nov
Cadmium, total [as Cd]daily maximumreport only (mg/L)Jan, Mar, Apr, Jun, Jul, Sep, Oct, Dec
Chromium, hexavalent [as Cr]daily maximumreport only (mg/L)Feb, May, Aug, Nov
Chromium, hexavalent [as Cr]daily maximumreport only (mg/L)Jan, Mar, Apr, Jun, Jul, Sep, Oct, Dec
Chromium, total [as Cr]daily maximumreport only (mg/L)Feb, May, Aug, Nov
Chromium, total [as Cr]daily maximumreport only (mg/L)Jan, Mar, Apr, Jun, Jul, Sep, Oct, Dec
Copper, total [as Cu]daily maximumreport only (mg/L)Feb, May, Aug, Nov
Copper, total [as Cu]daily maximumreport only (mg/L)Jan, Mar, Apr, Jun, Jul, Sep, Oct, Dec
Iron, total [as Fe]daily maximumreport only (mg/L)Feb, May, Aug, Nov
Iron, total [as Fe]daily maximumreport only (mg/L)Jan, Mar, Apr, Jun, Jul, Sep, Oct, Dec
Lead, total [as Pb]daily maximumreport only (mg/L)Feb, May, Aug, Nov
Lead, total [as Pb]daily maximumreport only (mg/L)Jan, Mar, Apr, Jun, Jul, Sep, Oct, Dec
Thallium, total [as Tl]daily maximumreport only (mg/L)Feb, May, Aug, Nov
Thallium, total [as Tl]daily maximumreport only (mg/L)Jan, Mar, Apr, Jun, Jul, Sep, Oct, Dec
Nickel, total [as Ni]daily maximumreport only (mg/L)Feb, May, Aug, Nov
Nickel, total [as Ni]daily maximumreport only (mg/L)Jan, Mar, Apr, Jun, Jul, Sep, Oct, Dec
Silver, total [as Ag]instantaneous maximumreport only (mg/L)Feb, May, Aug, Nov
Silver, total [as Ag]instantaneous maximumreport only (mg/L)Jan, Mar, Apr, Jun, Jul, Sep, Oct, Dec
Zinc, total [as Zn]daily maximumreport only (mg/L)Feb, May, Aug, Nov
Zinc, total [as Zn]daily maximumreport only (mg/L)Jan, Mar, Apr, Jun, Jul, Sep, Oct, Dec
Antimony, total [as Sb]daily maximumreport only (mg/L)Feb, May, Aug, Nov
Antimony, total [as Sb]daily maximumreport only (mg/L)Jan, Mar, Apr, Jun, Jul, Sep, Oct, Dec
Aluminum, total [as Al]daily maximumreport only (mg/L)Feb, May, Aug, Nov
Aluminum, total [as Al]daily maximumreport only (mg/L)Jan, Mar, Apr, Jun, Jul, Sep, Oct, Dec
Selenium, total [as Se]daily maximumreport only (mg/L)Feb, May, Aug, Nov
Selenium, total [as Se]daily maximumreport only (mg/L)Jan, Mar, Apr, Jun, Jul, Sep, Oct, Dec
Coliform, fecal - % samples exceeding limitinstantaneous maximum≤ 10 %May–Oct
Polychlorinated biphenyls [PCBs]instantaneous maximumreport only (mg/kg)Feb, Apr, Jun, Aug, Oct, Dec
Phenolsdaily maximumreport only (mg/L)Feb, May, Aug, Nov
Chlorine, total residualinstantaneous minimum≥ .2 mg/LMay–Oct
Chlorine, total residualinstantaneous maximum≤ 1.5 mg/LMay–Oct
Chlorine, total residualdaily maximumreport only (mg/L)Feb, May, Aug, Nov
Chlorine, total residualdaily maximumreport only (mg/L)Jan, Mar, Apr, Jun, Jul, Sep, Oct, Dec
Enterococci30-day geometric mean≤ 35 #/100mLMay–Oct
Enterococcimaximum≤ 500 #/100mLMay–Oct
Arsenic, sludge tot. dry wt [as As]instantaneous maximumreport only (mg/kg)Feb, Apr, Jun, Aug, Oct, Dec
Beryllium, sludge, tot. dry wt [as Be]instantaneous maximumreport only (mg/kg)Feb, Apr, Jun, Aug, Oct, Dec
Solids, total, percentinstantaneous minimumreport only (%)Feb, Apr, Jun, Aug, Oct, Dec
Solids, fixed, % of total solidsinstantaneous minimumreport only (%)Feb, Apr, Jun, Aug, Oct, Dec
Solids, volatile % of total solidsinstantaneous minimumreport only (%)Feb, Apr, Jun, Aug, Oct, Dec
Mercury, total [as Hg]daily maximumreport only (mg/L)Feb, May, Aug, Nov
Mercury, total [as Hg]daily maximumreport only (mg/L)Jan, Mar, Apr, Jun, Jul, Sep, Oct, Dec
Coliform, fecal general30-day geometric mean≤ 200 #/100mLMay–Oct
Coliform, fecal general30-day geometric mean≤ 88 #/100mLMay–Oct
Coliform, fecal general7-day geometric mean≤ 400 #/100mLMay–Oct
Zinc, sludge, total, dry weight [as Zn]instantaneous maximumreport only (mg/kg)Feb, Apr, Jun, Aug, Oct, Dec
Lead, sludge, total, dry weight [as Pb]instantaneous maximumreport only (mg/kg)Feb, Apr, Jun, Aug, Oct, Dec
Nickel, sludge, total, dry weight [as Ni]instantaneous maximumreport only (mg/kg)Feb, Apr, Jun, Aug, Oct, Dec
Mercury, sludge, total, dry weight [as Hg]instantaneous maximumreport only (mg/kg)Feb, Apr, Jun, Aug, Oct, Dec
Chromium, sludge, total, dry weight [as Cr]instantaneous maximumreport only (mg/kg)Feb, Apr, Jun, Aug, Oct, Dec
Copper, sludge, total, dry weight [as Cu]instantaneous maximumreport only (mg/kg)Feb, Apr, Jun, Aug, Oct, Dec
Cadmium, sludge, total, dry weight [as Cd]instantaneous maximumreport only (mg/kg)Feb, Apr, Jun, Aug, Oct, Dec
BOD, carbonaceous [5 day, 5 C]monthly average≤ 25 mg/Lall year
BOD, carbonaceous [5 day, 5 C]daily maximum≤ 45 mg/Lall year
BOD, carbonaceous [5 day, 5 C]monthly averagereport only (mg/L)all year
Solids, suspended percent removalminimum % removal≥ 85 %all year
Carbonaceous oxygen demand, % removalminimum % removal≥ 85 %all year
NOAEL Static 48Hr Acute D. pulexminimumreport only (% survival)Feb, May, Aug, Nov
NOAEL Static 48Hr Acute D. pulexminimumreport only (% survival)Jan, Mar, Apr, Jun, Jul, Sep, Oct, Dec
NOAEL Static 48Hr Acute Pimephales promelasminimumreport only (% survival)Feb, May, Aug, Nov

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/CT0100307 · MCP: https://passage-data.com/mcp