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Genon Holdco 10, LLC

Electric Services, major discharger, Sandwich, Massachusetts. NPDES permit MA0004928 expired Jun 23, 1994; its limits still apply. Last 12 months: over a limit once (last June 2026). Source: EPA ECHO, Oct 22, 2026.

Reports due
About 15 days after each period: outfall 001 form A monthly (5 values), outfall 002 form A monthly (5 values), outfall 010 form A monthly (6 values), outfall 011 form A monthly (12 values), outfall 012 form A monthly (7 values)
Last report on file
September 2026
Oct 2024 – Sep 2025
4 values over a limit, 0 required values missing, 0 of 60 reports late

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

Period endingParameterReportedLimitOver by
June 2026Temperature, water deg. fahrenheit, daily maximum86.6 deg F≤ 86 deg F1%

Limits in force (35)

ParameterStatisticLimitMonthsOutfall
Temperature, water deg. fahrenheitdaily maximum≤ 86 deg Fall year001
pHminimum≥ 6.5 SUall year001
pHmaximum≤ 8.5 SUall year001
Flow, in conduit or thru treatment plantdaily maximum≤ 518 MGDall year001
Chlorine, total residualdaily maximum≤ .1 mg/Lall year001
Temperature, water deg. fahrenheitdaily maximum≤ 90 deg Fall year002
pHminimum≥ 6.5 SUall year002
pHmaximum≤ 8.5 SUall year002
Flow, in conduit or thru treatment plantmonthly average≤ 2.5 MGDall year002
Flow, in conduit or thru treatment plantdaily maximum≤ 4.4 MGDall year002
pHminimum≥ 6.5 SUall year010
pHmaximum≤ 8.5 SUall year010
Oil & Greasemonthly average≤ 10 mg/Lall year010
Oil & Greasedaily maximum≤ 15 mg/Lall year010
Flow, in conduit or thru treatment plantmonthly average≤ .072 MGDall year010
Flow, in conduit or thru treatment plantdaily maximum≤ .144 MGDall year010
pHminimum≥ 6 SUall year011
pHmaximum≤ 9 SUall year011
Solids, total suspendedmonthly average≤ 30 mg/Lall year011
Solids, total suspendeddaily maximum≤ 100 mg/Lall year011
Oil & Greasemonthly average≤ 10 mg/Lall year011
Oil & Greasedaily maximum≤ 15 mg/Lall year011
Copper, total [as Cu]monthly average≤ 1 mg/Lall year011
Copper, total [as Cu]daily maximum≤ 1 mg/Lall year011
Iron, total [as Fe]monthly average≤ 1 mg/Lall year011
Iron, total [as Fe]daily maximum≤ 1 mg/Lall year011
Flow, in conduit or thru treatment plantmonthly average≤ .25 MGDall year011
Flow, in conduit or thru treatment plantdaily maximum≤ .4 MGDall year011
pHminimum≥ 6.5 SUall year012
pHmaximum≤ 8.5 SUall year012
Solids, total suspendedmonthly average≤ 30 mg/Lall year012
Solids, total suspendeddaily maximum≤ 100 mg/Lall year012
Oil & Greasedaily maximum≤ 15 mg/Lall year012
Flow, in conduit or thru treatment plantmonthly average≤ .07 MGDall year012
Flow, in conduit or thru treatment plantdaily maximum≤ .12 MGDall year012

How strict are these limits?

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

Same industry: the 6 Electric Services permits in Massachusetts.

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On EPA ECHO: Facility report · DMR history

Your permit document is the final word. As JSON: /api/v1/permits/MA0004928 · MCP: https://passage-data.com/mcp