City of Denham Springs — NPDES permit LA0045730: limits, due date and EPA's record

Sewage treatment plant, major discharger, Denham Springs, Louisiana. NPDES permit LA0045730 expired Oct 31, 2025; its limits still apply. Last 12 months: over a limit 56 times (last September 2026). Source: EPA ECHO, Oct 22, 2026.

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

Limits in force (95)

Period ending	Parameter	Reported	Limit	Over by
October 2025	BOD, carbonaceous [5 day, 20 C], monthly average	13 mg/L	≤ 5 mg/L	160%
October 2025	BOD, carbonaceous [5 day, 20 C], monthly average	274 lb/d	≤ 199 lb/d	38%
October 2025	BOD, carbonaceous [5 day, 20 C], weekly average	19 mg/L	≤ 10 mg/L	90%
October 2025	Nitrogen, ammonia total [as N], monthly average	2.57 mg/L	≤ 2 mg/L	29%
October 2025	Nitrogen, ammonia total [as N], weekly average	4.4 mg/L	≤ 4 mg/L	10%
November 2025	Coliform, fecal general, monthly geometric mean	220 #/100mL	≤ 200 #/100mL	10%
November 2025	Coliform, fecal general, weekly geometric mean	1000 #/100mL	≤ 400 #/100mL	150%
December 2025	BOD, carbonaceous [5 day, 20 C], monthly average	5.5 mg/L	≤ 5 mg/L	10%
January 2026	BOD, carbonaceous [5 day, 20 C], monthly average	24 mg/L	≤ 5 mg/L	380%
January 2026	BOD, carbonaceous [5 day, 20 C], monthly average	533 lb/d	≤ 199 lb/d	168%
January 2026	BOD, carbonaceous [5 day, 20 C], weekly average	65 mg/L	≤ 10 mg/L	550%
January 2026	Coliform, fecal general, weekly geometric mean	543 #/100mL	≤ 400 #/100mL	36%
January 2026	Nitrogen, ammonia total [as N], monthly average	163 lb/d	≤ 74 lb/d	120%
January 2026	Nitrogen, ammonia total [as N], monthly average	7.4 mg/L	≤ 2 mg/L	270%
January 2026	Nitrogen, ammonia total [as N], weekly average	16.5 mg/L	≤ 4 mg/L	313%
February 2026	BOD, carbonaceous [5 day, 20 C], monthly average	14 mg/L	≤ 5 mg/L	180%
February 2026	BOD, carbonaceous [5 day, 20 C], monthly average	293 lb/d	≤ 199 lb/d	47%
February 2026	BOD, carbonaceous [5 day, 20 C], weekly average	23 mg/L	≤ 10 mg/L	130%
February 2026	Nitrogen, ammonia total [as N], monthly average	153 lb/d	≤ 74 lb/d	107%
February 2026	Nitrogen, ammonia total [as N], monthly average	7.2 mg/L	≤ 2 mg/L	260%
February 2026	Nitrogen, ammonia total [as N], weekly average	15 mg/L	≤ 4 mg/L	275%
March 2026	BOD, carbonaceous [5 day, 20 C], monthly average	13.5 mg/L	≤ 5 mg/L	170%
March 2026	BOD, carbonaceous [5 day, 20 C], weekly average	14 mg/L	≤ 10 mg/L	40%
March 2026	Coliform, fecal general, weekly geometric mean	2950 #/100mL	≤ 400 #/100mL	638%
March 2026	Nitrogen, ammonia total [as N], monthly average	4.7 mg/L	≤ 2 mg/L	135%
March 2026	Nitrogen, ammonia total [as N], monthly average	80 lb/d	≤ 74 lb/d	8%
March 2026	Nitrogen, ammonia total [as N], weekly average	7.5 mg/L	≤ 4 mg/L	88%
March 2026	Solids, total suspended, monthly average	44 mg/L	≤ 15 mg/L	193%
March 2026	Solids, total suspended, monthly average	903 lb/d	≤ 751 lb/d	20%
March 2026	Solids, total suspended, weekly average	157 mg/L	≤ 23 mg/L	583%
April 2026	BOD, carbonaceous [5 day, 20 C], monthly average	14 mg/L	≤ 5 mg/L	180%
April 2026	BOD, carbonaceous [5 day, 20 C], monthly average	287 lb/d	≤ 199 lb/d	44%
April 2026	BOD, carbonaceous [5 day, 20 C], weekly average	26 mg/L	≤ 10 mg/L	160%
April 2026	Coliform, fecal general, weekly geometric mean	1000 #/100mL	≤ 400 #/100mL	150%
April 2026	Solids, total suspended, weekly average	25 mg/L	≤ 23 mg/L	9%
May 2026	BOD, carbonaceous [5 day, 20 C], monthly average	6.2 mg/L	≤ 5 mg/L	24%
May 2026	Coliform, fecal general, weekly geometric mean	1000 #/100mL	≤ 400 #/100mL	150%
May 2026	Nitrogen, ammonia total [as N], monthly average	2.5 mg/L	≤ 2 mg/L	25%
May 2026	Nitrogen, ammonia total [as N], weekly average	6.8 mg/L	≤ 4 mg/L	70%
May 2026	Solids, total suspended, monthly average	39 mg/L	≤ 15 mg/L	160%
May 2026	Solids, total suspended, monthly average	989 lb/d	≤ 751 lb/d	32%
May 2026	Solids, total suspended, weekly average	106.5 mg/L	≤ 23 mg/L	363%
June 2026	BOD, carbonaceous [5 day, 20 C], monthly average	8.02 mg/L	≤ 5 mg/L	60%
June 2026	BOD, carbonaceous [5 day, 20 C], weekly average	13.85 mg/L	≤ 10 mg/L	39%
July 2026	BOD, carbonaceous [5 day, 20 C], monthly average	11 mg/L	≤ 5 mg/L	120%
July 2026	BOD, carbonaceous [5 day, 20 C], monthly average	302 lb/d	≤ 199 lb/d	52%
July 2026	BOD, carbonaceous [5 day, 20 C], weekly average	18.7 mg/L	≤ 10 mg/L	87%
July 2026	Coliform, fecal general, weekly geometric mean	1000 #/100mL	≤ 400 #/100mL	150%
July 2026	Nitrogen, ammonia total [as N], monthly average	120 lb/d	≤ 74 lb/d	62%
July 2026	Nitrogen, ammonia total [as N], monthly average	4.5 mg/L	≤ 2 mg/L	125%
July 2026	Nitrogen, ammonia total [as N], weekly average	16.45 mg/L	≤ 4 mg/L	311%
August 2026	BOD, carbonaceous [5 day, 20 C], monthly average	28 mg/L	≤ 5 mg/L	460%
August 2026	BOD, carbonaceous [5 day, 20 C], monthly average	589 lb/d	≤ 199 lb/d	196%
August 2026	BOD, carbonaceous [5 day, 20 C], weekly average	48 mg/L	≤ 10 mg/L	380%
August 2026	Nitrogen, ammonia total [as N], weekly average	5 mg/L	≤ 4 mg/L	25%
September 2026	BOD, carbonaceous [5 day, 20 C], monthly average	5.5 mg/L	≤ 5 mg/L	10%

Parameter	Statistic	Limit	Months	Outfall
Oxygen, dissolved [DO]	monthly average minimum	≥ 5 mg/L	all year	001
pH	instantaneous minimum	≥ 6 SU	all year	001
pH	instantaneous maximum	≤ 8.5 SU	all year	001
Solids, total suspended	monthly average	≤ 15 mg/L	all year	001
Solids, total suspended	weekly average	≤ 23 mg/L	all year	001
Solids, total suspended	monthly average	≤ 751 lb/d	all year	001
Nitrogen, total [as N]	monthly average	report only (mg/L)	all year	001
Nitrogen, total [as N]	weekly average	report only (mg/L)	all year	001
Nitrogen, total [as N]	monthly average	report only (lb/d)	all year	001
Nitrogen, ammonia total [as N]	monthly average	≤ 2 mg/L	all year	001
Nitrogen, ammonia total [as N]	weekly average	≤ 4 mg/L	all year	001
Nitrogen, ammonia total [as N]	monthly average	≤ 74 lb/d	all year	001
Phosphorus, total [as P]	monthly average	report only (mg/L)	all year	001
Phosphorus, total [as P]	weekly average	report only (mg/L)	all year	001
Phosphorus, total [as P]	monthly average	report only (lb/d)	all year	001
Chloride [as Cl]	monthly average	report only (mg/L)	all year	001
Chloride [as Cl]	weekly average	report only (mg/L)	all year	001
Chloride [as Cl]	monthly average	report only (lb/d)	all year	001
Sulfate, total [as SO4]	monthly average	report only (mg/L)	all year	001
Sulfate, total [as SO4]	weekly average	report only (mg/L)	all year	001
Sulfate, total [as SO4]	monthly average	report only (lb/d)	all year	001
Whole effluent toxicity - retest #1	7-day minimum	report only (pass=0;fail=1)	all year	001
Whole effluent toxicity - retest #1	monthly average minimum	report only (pass=0;fail=1)	all year	001
Whole effluent toxicity - retest #2	7-day minimum	report only (pass=0;fail=1)	all year	001
Whole effluent toxicity - retest #2	monthly average minimum	report only (pass=0;fail=1)	all year	001
WET, sublethal retest #1	7-day minimum	report only (pass=0;fail=1)	all year	001
WET, sublethal retest #1	monthly average minimum	report only (pass=0;fail=1)	all year	001
WET, sublethal retest #2	7-day minimum	report only (pass=0;fail=1)	all year	001
WET, sublethal retest #2	monthly average minimum	report only (pass=0;fail=1)	all year	001
Flow, in conduit or thru treatment plant	monthly average	report only (MGD)	all year	001
Flow, in conduit or thru treatment plant	weekly average	report only (MGD)	all year	001
Chlorine, total residual	instantaneous maximum	≤ .033 mg/L	all year	001
Whole Effluent Toxicity - Retest #3	7-day minimum	report only (pass=0;fail=1)	all year	001
Whole Effluent Toxicity - Retest #3	monthly average minimum	report only (pass=0;fail=1)	all year	001
Whole Effluent Toxicity, Sub-Lethal Retest #3	7-day minimum	report only (pass=0;fail=1)	all year	001
Whole Effluent Toxicity, Sub-Lethal Retest #3	monthly average minimum	report only (pass=0;fail=1)	all year	001
Whole Effluent Toxicity [WET] - P. promelas	7-day minimum	≥ 99 %	all year	001
Whole Effluent Toxicity [WET] - P. promelas	monthly average minimum	≥ 99 %	all year	001
Solids, total dissolved	monthly average	report only (mg/L)	all year	001
Solids, total dissolved	weekly average	report only (mg/L)	all year	001
Solids, total dissolved	monthly average	report only (lb/d)	all year	001
Coliform, fecal general	monthly geometric mean	≤ 200 #/100mL	all year	001
Coliform, fecal general	weekly geometric mean	≤ 400 #/100mL	all year	001
BOD, carbonaceous [5 day, 20 C]	monthly average	≤ 5 mg/L	all year	001
BOD, carbonaceous [5 day, 20 C]	weekly average	≤ 10 mg/L	all year	001
BOD, carbonaceous [5 day, 20 C]	monthly average	≤ 199 lb/d	all year	001
Pass/Fail Static Renewal 7 Day Chronic Ceriodaphnia dubia	7-day minimum	report only (pass=0;fail=1)	all year	001
Pass/Fail Static Renewal 7 Day Chronic Ceriodaphnia dubia	monthly average minimum	report only (pass=0;fail=1)	all year	001
Pass/Fail Static Renewal 7Day Chronic Pimephales promelas	7-day minimum	report only (pass=0;fail=1)	all year	001
Pass/Fail Static Renewal 7Day Chronic Pimephales promelas	monthly average minimum	report only (pass=0;fail=1)	all year	001
Low Flow Pass/Fail Survival Test Static Renewal 7 Day Chronic Ceriodaphnia dubia	7-day minimum	report only (pass=0;fail=1)	all year	001
Low Flow Pass/Fail Survival Test Static Renewal 7 Day Chronic Ceriodaphnia dubia	monthly average minimum	report only (pass=0;fail=1)	all year	001
Low Flow Pass/Fail Survival Test Static Renewal 7 Day Chronic Pimephales promelas	7-day minimum	report only (pass=0;fail=1)	all year	001
Low Flow Pass/Fail Survival Test Static Renewal 7 Day Chronic Pimephales promelas	monthly average minimum	report only (pass=0;fail=1)	all year	001
NOEC Lethal Static Renewal 7 Day Chronic Ceriodaphnia dubia	7-day minimum	report only (%)	all year	001
NOEC Lethal Static Renewal 7 Day Chronic Ceriodaphnia dubia	monthly average minimum	report only (%)	all year	001
NOEC Lethal Static Renewal 7 Day Chronic Pimephales promelas	7-day minimum	report only (%)	all year	001
NOEC Lethal Static Renewal 7 Day Chronic Pimephales promelas	monthly average minimum	report only (%)	all year	001
NOEC Sub-Lethal Static Renewal 7 Day Chronic Ceriodaphnia dubia	7-day minimum	report only (%)	all year	001
NOEC Sub-Lethal Static Renewal 7 Day Chronic Ceriodaphnia dubia	monthly average minimum	report only (%)	all year	001
NOEC Sub-Lethal Static Renewal 7 Day Chronic Pimephales promelas	7-day minimum	report only (%)	all year	001
NOEC Sub-Lethal Static Renewal 7 Day Chronic Pimephales promelas	monthly average minimum	report only (%)	all year	001
Coef Of Var Static Renewal 7Day Chronic Ceriodaphnia dubia	maximum	report only (%)	all year	001
Coef Of Var Static Renewal 7Day Chronic Pimephales promelas	maximum	report only (%)	all year	001
Oxygen, dissolved [DO]	monthly average minimum	≥ 5 mg/L	all year	002
pH	instantaneous minimum	≥ 6 SU	all year	002
pH	instantaneous maximum	≤ 8.5 SU	all year	002
Solids, total suspended	monthly average	≤ 15 mg/L	all year	002
Solids, total suspended	weekly average	≤ 23 mg/L	all year	002
Solids, total suspended	monthly average	≤ 77 lb/d	all year	002
Nitrogen, total [as N]	monthly average	report only (mg/L)	all year	002
Nitrogen, total [as N]	weekly average	report only (mg/L)	all year	002
Nitrogen, total [as N]	monthly average	report only (lb/d)	all year	002
Nitrogen, ammonia total [as N]	monthly average	≤ 5 mg/L	all year	002
Nitrogen, ammonia total [as N]	weekly average	≤ 10 mg/L	all year	002
Nitrogen, ammonia total [as N]	monthly average	≤ 26 lb/d	all year	002
Phosphorus, total [as P]	monthly average	report only (mg/L)	all year	002
Phosphorus, total [as P]	weekly average	report only (mg/L)	all year	002
Phosphorus, total [as P]	monthly average	report only (lb/d)	all year	002
Chloride [as Cl]	monthly average	report only (mg/L)	all year	002
Chloride [as Cl]	weekly average	report only (mg/L)	all year	002
Chloride [as Cl]	monthly average	report only (lb/d)	all year	002
Sulfate, total [as SO4]	monthly average	report only (mg/L)	all year	002
Sulfate, total [as SO4]	weekly average	report only (mg/L)	all year	002
Sulfate, total [as SO4]	monthly average	report only (lb/d)	all year	002
Flow, in conduit or thru treatment plant	monthly average	report only (MGD)	all year	002
Flow, in conduit or thru treatment plant	weekly average	report only (MGD)	all year	002
Solids, total dissolved	monthly average	report only (mg/L)	all year	002
Solids, total dissolved	weekly average	report only (mg/L)	all year	002
Solids, total dissolved	monthly average	report only (lb/d)	all year	002
Coliform, fecal general	monthly geometric mean	≤ 200 #/100mL	all year	002
Coliform, fecal general	weekly geometric mean	≤ 400 #/100mL	all year	002
BOD, carbonaceous [5 day, 20 C]	monthly average	≤ 10 mg/L	all year	002
BOD, carbonaceous [5 day, 20 C]	weekly average	≤ 15 mg/L	all year	002
BOD, carbonaceous [5 day, 20 C]	monthly average	≤ 51 lb/d	all year	002

How strict are these limits?

Your permit document is the final word. As JSON: /api/v1/permits/LA0045730 · MCP: https://passage-data.com/mcp