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Ledyard Water Pollution

Sewage treatment plant, Ledyard, Connecticut. NPDES permit CT0101681 expired Jun 30, 2025; its limits still apply. Last 12 months: over a limit 4 times (last January 2026). Source: EPA ECHO, Oct 22, 2026.

Reports due
About 31 days after each period: form 1 monthly (47 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

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

Period endingParameterReportedLimitOver by
January 2026BOD, 5-day, 20 deg. C, daily maximum17 mg/L≤ 15 mg/L13%
January 2026Solids, suspended percent removal, minimum % removal79 %≥ 90 %110%
January 2026Solids, total suspended, daily maximum41 mg/L≤ 15 mg/L173%
January 2026Solids, total suspended, monthly average11 mg/L≤ 10 mg/L10%

Limits in force (60)

ParameterStatisticLimitMonths
Flow ratemonthly averagereport only (MGD)all year
Flow ratedaily maximumreport only (MGD)all year
BOD, 5-day, 20 deg. Cmonthly average≤ 10 mg/Lall year
BOD, 5-day, 20 deg. Cdaily maximum≤ 15 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≤ 10 mg/Lall year
Solids, total suspendeddaily maximum≤ 15 mg/Lall year
Solids, total suspendedmonthly averagereport only (mg/L)all year
Solids, total suspendeddaily maximumreport only (mg/L)Mar, Jun, Sep, Dec
Nitrogen, total [as N]daily maximum≤ 10 mg/Lall year
Nitrogen, ammonia total [as N]monthly average≤ 1.4 mg/LJun–Oct
Nitrogen, ammonia total [as N]daily maximum≤ 2.8 mg/LJun–Oct
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]daily maximumreport only (mg/L)all year
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
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 residualdaily maximumreport only (mg/L)Mar, Jun, Sep, Dec
E. coli30-day geometric mean≤ 126 #/100mLall year
E. colimaximum≤ 410 #/100mLall year
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≥ 90 %all year
Solids, suspended percent removalminimum % removal≥ 90 %all year
NOAEL Static 48Hr Acute D. pulexminimum≥ 90 % survivalMar, Jun, Sep, Dec
NOAEL Static 48Hr Acute Pimephales promelasminimum≥ 90 % survivalMar, Jun, Sep, Dec

How strict are these limits?

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

Check this month's numbers Email me before each report is due

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On EPA ECHO: Facility report · DMR history

Your permit document is the final word. As JSON: /api/v1/permits/CT0101681 · MCP: https://passage-data.com/mcp