Loudoun County Sanitation Authority — NPDES permit VA0091383: limits, due date and EPA's record

Sewerage Systems, major discharger, Ashburn, Virginia. NPDES permit VA0091383, in force until Jul 31, 2028. Last 12 months: over a limit 2 times (last December 2025). Source: EPA ECHO, Oct 22, 2026.

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

Period ending	Parameter	Reported	Limit	Over by
December 2025	Chlorine, total residual, average	2.5	≤ .016 mg/L	15525%
December 2025	Chlorine, total residual, maximum	2.5	≤ .016 mg/L	15525%

Limits in force (113)

Parameter	Statistic	Limit	Months	Outfall
Turbidity	monthly average	≤ .5 NTU	all year	001
Turbidity	monthly average	≤ .5 NTU	all year	001
Oxygen, dissolved [DO]	instantaneous minimum	≥ 6 mg/L	all year	001
Oxygen, dissolved [DO]	minimum	≥ 6 mg/L	all year	001
Oxygen demand, chem. [low level] [COD]	monthly average	≤ 10 mg/L	all year	001
Oxygen demand, chem. [low level] [COD]	monthly average	≤ 10 mg/L	all year	001
Oxygen demand, chem. [low level] [COD]	weekly average	≤ 15 mg/L	all year	001
Oxygen demand, chem. [low level] [COD]	weekly average	≤ 20 mg/L	all year	001
Oxygen demand, chem. [low level] [COD]	monthly average	≤ 420 kg/d	all year	001
Oxygen demand, chem. [low level] [COD]	monthly average	≤ 620 kg/d	all year	001
Oxygen demand, chem. [low level] [COD]	weekly average	≤ 620 kg/d	all year	001
Oxygen demand, chem. [low level] [COD]	weekly average	≤ 1250 kg/d	all year	001
pH	instantaneous minimum	≥ 6 SU	all year	001
pH	minimum	≥ 6 SU	all year	001
pH	instantaneous maximum	≤ 9 SU	all year	001
pH	maximum	≤ 9 SU	all year	001
Solids, total suspended	monthly average	≤ 1 mg/L	all year	001
Solids, total suspended	monthly average	≤ 1 mg/L	all year	001
Solids, total suspended	weekly average	≤ 1.5 mg/L	all year	001
Solids, total suspended	weekly average	≤ 2 mg/L	all year	001
Solids, total suspended	monthly average	≤ 42 kg/d	all year	001
Solids, total suspended	monthly average	≤ 62 kg/d	all year	001
Solids, total suspended	weekly average	≤ 62 kg/d	all year	001
Solids, total suspended	weekly average	≤ 120 kg/d	all year	001
Nitrogen, total [as N]	monthly average	report only (mg/L)	all year	001
Nitrogen, total [as N]	monthly average	report only (mg/L)	all year	001
Nitrogen, Kjeldahl, total [as N]	monthly average	≤ 1 mg/L	all year	001
Nitrogen, Kjeldahl, total [as N]	monthly average	≤ 1 mg/L	all year	001
Nitrogen, Kjeldahl, total [as N]	weekly average	≤ 1.5 mg/L	all year	001
Nitrogen, Kjeldahl, total [as N]	weekly average	≤ 2 mg/L	all year	001
Nitrogen, Kjeldahl, total [as N]	monthly average	≤ 92 lb/d	all year	001
Nitrogen, Kjeldahl, total [as N]	monthly average	≤ 140 lb/d	all year	001
Nitrogen, Kjeldahl, total [as N]	weekly average	≤ 140 lb/d	all year	001
Nitrogen, Kjeldahl, total [as N]	weekly average	≤ 280 lb/d	all year	001
Nitrite + Nitrate total [as N]	monthly average	report only (mg/L)	all year	001
Nitrite + Nitrate total [as N]	monthly average	report only (mg/L)	all year	001
Phosphorus, total [as P]	monthly average	≤ .1 mg/L	all year	001
Phosphorus, total [as P]	monthly average	≤ .1 mg/L	all year	001
Phosphorus, total [as P]	weekly average	≤ .15 mg/L	all year	001
Phosphorus, total [as P]	weekly average	≤ .2 mg/L	all year	001
Phosphorus, total [as P]	monthly average	≤ 9.2 lb/d	all year	001
Phosphorus, total [as P]	monthly average	≤ 14 lb/d	all year	001
Phosphorus, total [as P]	weekly average	≤ 14 lb/d	all year	001
Phosphorus, total [as P]	weekly average	≤ 28 lb/d	all year	001
Flow, in conduit or thru treatment plant	monthly average	≤ 11 MGD (alert, not enforceable)	all year	001
Flow, in conduit or thru treatment plant	monthly average	≤ 16.5 MGD (alert, not enforceable)	all year	001
Flow, in conduit or thru treatment plant	daily maximum	report only (MGD) (alert, not enforceable)	all year	001
Flow, in conduit or thru treatment plant	daily maximum	report only (MGD) (alert, not enforceable)	all year	001
E. coli	monthly geometric mean	≤ 2 #/100mL	all year	001
E. coli	monthly geometric mean	≤ 2 #/100mL	all year	001
Nitrogen, Total As N	annual average	≤ 4 mg/L	all year	001
Nitrogen, Total As N	annual average	≤ 3 mg/L	all year	001
Phosphorus, Total As P	monthly average	≤ .1 mg/L	all year	001
TU Static Renewal 7-Day Chronic Ceriodaphnia dubia	maximum	report only (tox chronic)	all year	001
TU Static Renewal 7-Day Chronic Ceriodaphnia dubia	maximum	report only (tox chronic)	all year	001
TU Static Renewal 7-Day Chronic Pimphales promelas	maximum	report only (tox chronic)	all year	001
TU Static Renewal 7-Day Chronic Pimphales promelas	maximum	report only (tox chronic)	all year	001
pH	minimum	≥ 6 SU	all year	002
pH	maximum	≤ 9 SU	all year	002
Solids, total suspended	average	report only (mg/L)	all year	002
Solids, total suspended	maximum	report only (mg/L)	all year	002
Flow, in conduit or thru treatment plant	average	report only (MGD) (alert, not enforceable)	all year	002
Flow, in conduit or thru treatment plant	maximum	report only (MGD) (alert, not enforceable)	all year	002
Chlorine, total residual	average	≤ .016 mg/L	all year	002
Chlorine, total residual	maximum	≤ .016 mg/L	all year	002
pH	minimum	≥ 6 SU	all year	003
pH	maximum	≤ 9 SU	all year	003
Solids, total suspended	average	report only (mg/L)	all year	003
Solids, total suspended	maximum	report only (mg/L)	all year	003
Flow, in conduit or thru treatment plant	average	report only (MGD) (alert, not enforceable)	all year	003
Flow, in conduit or thru treatment plant	maximum	report only (MGD) (alert, not enforceable)	all year	003
Chlorine, total residual	average	≤ .016 mg/L	all year	003
Chlorine, total residual	maximum	≤ .016 mg/L	all year	003
pH	minimum	≥ 6 SU	all year	004
pH	maximum	≤ 9 SU	all year	004
Solids, total suspended	average	report only (mg/L)	all year	004
Solids, total suspended	maximum	report only (mg/L)	all year	004
Flow, in conduit or thru treatment plant	average	report only (MGD) (alert, not enforceable)	all year	004
Flow, in conduit or thru treatment plant	maximum	report only (MGD) (alert, not enforceable)	all year	004
Chlorine, total residual	average	≤ .016 mg/L	all year	004
Chlorine, total residual	maximum	≤ .016 mg/L	all year	004
pH	minimum	≥ 6 SU	all year	005
pH	maximum	≤ 9 SU	all year	005
Solids, total suspended	average	report only (mg/L)	all year	005
Solids, total suspended	maximum	report only (mg/L)	all year	005
Flow, in conduit or thru treatment plant	average	report only (MGD) (alert, not enforceable)	all year	005
Flow, in conduit or thru treatment plant	maximum	report only (MGD) (alert, not enforceable)	all year	005
Chlorine, total residual	average	≤ .016 mg/L	all year	005
Chlorine, total residual	maximum	≤ .016 mg/L	all year	005
pH	minimum	≥ 6 SU	all year	006
pH	maximum	≤ 9 SU	all year	006
Solids, total suspended	average	report only (mg/L)	all year	006
Solids, total suspended	maximum	report only (mg/L)	all year	006
Flow, in conduit or thru treatment plant	average	report only (MGD) (alert, not enforceable)	all year	006
Flow, in conduit or thru treatment plant	maximum	report only (MGD) (alert, not enforceable)	all year	006
Chlorine, total residual	average	≤ .016 mg/L	all year	006
Chlorine, total residual	maximum	≤ .016 mg/L	all year	006
pH	minimum	≥ 6 SU	all year	007
pH	maximum	≤ 9 SU	all year	007
Solids, total suspended	average	report only (mg/L)	all year	007
Solids, total suspended	maximum	report only (mg/L)	all year	007
Flow, in conduit or thru treatment plant	average	report only (MGD) (alert, not enforceable)	all year	007
Flow, in conduit or thru treatment plant	maximum	report only (MGD) (alert, not enforceable)	all year	007
Chlorine, total residual	average	≤ .016 mg/L	all year	007
Chlorine, total residual	maximum	≤ .016 mg/L	all year	007
pH	minimum	≥ 6 SU	all year	008
pH	maximum	≤ 9 SU	all year	008
Solids, total suspended	average	report only (mg/L)	all year	008
Solids, total suspended	maximum	report only (mg/L)	all year	008
Flow, in conduit or thru treatment plant	average	report only (MGD) (alert, not enforceable)	all year	008
Flow, in conduit or thru treatment plant	maximum	report only (MGD) (alert, not enforceable)	all year	008
Chlorine, total residual	average	≤ .016 mg/L	all year	008
Chlorine, total residual	maximum	≤ .016 mg/L	all year	008

How strict are these limits?

Your permit document is the final word. As JSON: /api/v1/permits/VA0091383 · MCP: https://passage-data.com/mcp