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Thompson WPCF

Sewage treatment plant, major discharger, Thompson, Connecticut. NPDES permit CT0100706 expired Jun 30, 2023; its limits still apply. Last 12 months: over a limit 2 times (last October 2025). Source: EPA ECHO, Oct 22, 2026.

Reports due
About 15 days after each period: form 1 monthly (46 values)
Last report on file
September 2026
Oct 2024 – Sep 2025
1 value over a limit, 0 required values missing, 1 of 12 reports late

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

Period endingParameterReportedLimitOver by
October 2025Phosphorus, total [as P], daily maximum2.44 mg/L≤ 2.18 mg/L12%
October 2025Phosphorus, total [as P], monthly average1.62 mg/L≤ 1.09 mg/L49%

Limits in force (61)

ParameterStatisticLimitMonths
Flow ratemonthly averagereport only (MGD)all year
Flow ratedaily maximumreport only (MGD)all year
BOD, 5-day, 20 deg. Cmonthly average≤ 30 mg/Lall year
BOD, 5-day, 20 deg. Cdaily maximum≤ 50 mg/Lall year
BOD, 5-day, 20 deg. Cmonthly averagereport only (mg/L)all year
BOD, 5-day, 20 deg. Cdaily maximumreport only (mg/L)Mar, Jun, Sep, 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)Mar, Jun, Sep, Dec
Nitrogen, ammonia total [as N]daily maximumreport only (mg/L)Mar, Jun, Sep, Dec
Nitrogen, nitrite total [as N]daily maximumreport only (mg/L)Mar, Jun, Sep, Dec
Nitrogen, nitrate total [as N]daily maximumreport only (mg/L)Mar, Jun, Sep, Dec
Phosphorus, total [as P]monthly average≤ 1.09 mg/LApr–Oct
Phosphorus, total [as P]daily maximumreport only (mg/L)Jan, Feb, Mar, Nov, Dec
Phosphorus, total [as P]daily maximum≤ 2.18 mg/LApr–Oct
Phosphorus, total [as P]daily maximumreport only (mg/L)Mar, Jun, Sep, Dec
Cyanide, total [as CN]daily maximumreport only (mg/L)Mar, Jun, Sep, Dec
Cyanide, free [amenable to chlorination]daily maximumreport only (mg/L)Mar, Jun, Sep, Dec
Arsenic, total [as As]daily maximumreport only (mg/L)Mar, Jun, Sep, Dec
Beryllium, total [as Be]daily maximumreport only (mg/L)Mar, Jun, Sep, Dec
Cadmium, total [as Cd]daily maximumreport only (mg/L)Mar, Jun, Sep, Dec
Chromium, hexavalent [as Cr]daily maximumreport only (mg/L)Mar, Jun, Sep, Dec
Chromium, total [as Cr]daily maximumreport only (mg/L)Mar, Jun, Sep, Dec
Copper, total [as Cu]daily maximumreport only (mg/L)Mar, Jun, Sep, Dec
Iron, total [as Fe]daily maximumreport only (mg/L)Mar, Jun, Sep, Dec
Lead, total [as Pb]daily maximumreport only (mg/L)Mar, Jun, Sep, Dec
Thallium, total [as Tl]daily maximumreport only (mg/L)Mar, Jun, Sep, Dec
Nickel, total [as Ni]daily maximumreport only (mg/L)Mar, Jun, Sep, Dec
Silver, total [as Ag]daily maximumreport only (mg/L)Mar, Jun, Sep, Dec
Zinc, total [as Zn]daily maximumreport only (mg/L)Mar, Jun, Sep, Dec
Antimony, total [as Sb]daily maximumreport only (mg/L)Mar, Jun, Sep, Dec
Aluminum, total [as Al]daily maximumreport only (mg/L)Mar, Jun, Sep, Dec
Selenium, total [as Se]daily maximumreport only (mg/L)Mar, Jun, Sep, Dec
Polychlorinated biphenyls [PCBs]instantaneous maximumreport only (mg/kg)Jun, Dec
Phenolsdaily maximumreport only (mg/L)Mar, Jun, Sep, Dec
Chlorine, total residualmonthly average≤ .1 mg/LMay–Sep
Chlorine, total residualinstantaneous maximum≤ .1 mg/LMay–Sep
Chlorine, total residualdaily maximumreport only (mg/L)Mar, Jun, Sep, Dec
E. coli30-day geometric mean≤ 126 #/100mLMay–Sep
E. colimaximum≤ 410 #/100mLMay–Sep
Phosphorus, Total [Avg Seasonal Load Cap]monthly average≤ 2.1 lb/dOct
Arsenic, sludge tot. dry wt [as As]instantaneous maximumreport only (mg/kg)Jun, Dec
Beryllium, sludge, tot. dry wt [as Be]instantaneous maximumreport only (mg/kg)Jun, Dec
Solids, total, percentinstantaneous minimumreport only (%)Jun, Dec
Solids, fixed, % of total solidsinstantaneous minimumreport only (%)Jun, Dec
Solids, volatile % of total solidsinstantaneous minimumreport only (%)Jun, Dec
Mercury, total [as Hg]daily maximumreport only (mg/L)Mar, Jun, Sep, Dec
Zinc, sludge, total, dry weight [as Zn]instantaneous maximumreport only (mg/kg)Jun, Dec
Lead, sludge, total, dry weight [as Pb]instantaneous maximumreport only (mg/kg)Jun, Dec
Nickel, sludge, total, dry weight [as Ni]instantaneous maximumreport only (mg/kg)Jun, Dec
Mercury, sludge, total, dry weight [as Hg]instantaneous maximumreport only (mg/kg)Jun, Dec
Chromium, sludge, total, dry weight [as Cr]instantaneous maximumreport only (mg/kg)Jun, Dec
Copper, sludge, total, dry weight [as Cu]instantaneous maximumreport only (mg/kg)Jun, Dec
Cadmium, sludge, total, dry weight [as Cd]instantaneous maximumreport only (mg/kg)Jun, Dec
BOD, 5-day, percent removalminimum % removal≥ 85 %all year
Solids, suspended percent removalminimum % removal≥ 85 %all year
NOAEL Static 48Hr Acute D. pulexminimumreport only (% survival)Mar, Jun, Sep, Dec
NOAEL Static 48Hr Acute Pimephales promelasminimumreport only (% survival)Mar, Jun, Sep, Dec

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/CT0100706 · MCP: https://passage-data.com/mcp