Clean Water Act discharge permit · NPDES TX0024287

NORTH MUSTANG ISLAND WWTP, Port Aransas, TX: NPDES TX0024287 discharge permit, effluent exceedances, inspections, penalties

Administratively continuedPermit status
MajorDischarger class
55Pollutants under a numeric limit
6Pollutants with an effluent exceedance
0Inspections on file
0Formal enforcement actions

NORTH MUSTANG ISLAND WWTP, held by NUECES COUNTY WCID 4, holds NPDES permit TX0024287, which discharges to Fw Pond/Marsh;E Flats Portion Of Cc Bay. EPA’s file records it issued June 18, 2020 and expiring June 18, 2025.

NORTH MUSTANG ISLAND WWTP, Port Aransas, Texas: Individual permit TX0024287, held by NUECES COUNTY WCID 4; Publicly owned treatment works; Administratively continued (past its expiration date and still in force until reissued); issued June 18, 2020, term to June 18, 2025; discharges to FW POND/MARSH;E FLATS PORTION OF CC BAY.

Solids, total suspended: 3 limits, 19 violations of any kind, 7 effluent exceedances, latest July 31, 2021, largest 135% over the limit.
Enterococci: 0 limits, 12 violations of any kind, 7 effluent exceedances, latest June 30, 2019, largest 2,226% over the limit.
Chlorine, total residual: 2 limits, 11 violations of any kind, 3 effluent exceedances, latest September 30, 2010, largest 550% over the limit.
Nitrogen, ammonia total [as N]: 3 limits, 11 violations of any kind, 2 effluent exceedances, latest February 28, 2021, largest 100% over the limit.
E. coli: 2 limits, 2 violations of any kind, 2 effluent exceedances, latest April 30, 2023, largest 105% over the limit.
BOD, 5-day, 20 deg. C: 0 limits, 4 violations of any kind, 1 effluent exceedance, latest March 31, 2003, largest 40% over the limit.
Flow, in conduit or thru treatment plant: 4 limits, 31 violations of any kind, 0 effluent exceedances.
Zinc, total [as Zn]: 0 limits, 27 violations of any kind, 0 effluent exceedances.
pH: 3 limits, 9 violations of any kind, 0 effluent exceedances.
BOD, carbonaceous [5 day, 20 C]: 3 limits, 9 violations of any kind, 0 effluent exceedances.
NOEC Lethal Static Renewal 7 Day Chronic Menidia menidia: 0 limits, 5 violations of any kind, 0 effluent exceedances.
Low Flow Pass/Fail Survival Test Static Renewal 7 Day Chronic Ceriodaphnia dubia: 2 limits, 4 violations of any kind, 0 effluent exceedances.
NOEC Lethal Static Renewal 7 Day Chronic Ceriodaphnia dubia: 2 limits, 4 violations of any kind, 0 effluent exceedances.
NOEC Sub-Lethal Static Renewal 7 Day Chronic Ceriodaphnia dubia: 2 limits, 4 violations of any kind, 0 effluent exceedances.
Pass/Fail Sub-Lethal Static Renewal 7 Day Chronic Ceriodaphnia dubia: 2 limits, 4 violations of any kind, 0 effluent exceedances.
LOEC Lethal Survival Static Renewal 7 Day Chronic Ceriodaphnia dubia: 2 limits, 4 violations of any kind, 0 effluent exceedances.
LOEC Sub-Lethal Reproduction Static Renewal 7 Day Chronic Ceriodaphnia dubia: 2 limits, 4 violations of any kind, 0 effluent exceedances.
Oxygen, dissolved [DO]: 1 limit, 4 violations of any kind, 0 effluent exceedances.
LOEC Lethal Survival Static Renewal 7 Day Chronic Americamysis bahia (formerly Mysidopsis bahia): 0 limits, 4 violations of any kind, 0 effluent exceedances.
LOEC Lethal Survival Static Renewal 7 Day Chronic Menidia menidia: 0 limits, 4 violations of any kind, 0 effluent exceedances.
LOEC Sub-Lethal Reproduction Static Renewal 7 Day Chronic Americamysis bahia (Mysidopsis bahia): 0 limits, 4 violations of any kind, 0 effluent exceedances.
LOEC Sub-Lethal Reproduction Static Renewal 7 Day Chronic Menidia menidia: 0 limits, 4 violations of any kind, 0 effluent exceedances.
Low Flow Pass/Fail Survival Test Static Renewal 7 Day Chronic Americamysis bahia (Mysidopsis bahia): 0 limits, 3 violations of any kind, 0 effluent exceedances.
Low Flow Pass/Fail Survival Test Static Renewal 7 Day Chronic Menidia menidia: 0 limits, 3 violations of any kind, 0 effluent exceedances.
NOEC Lethal Static Renewal 7 Day Chronic Americamysis bahia (formerly Mysidopsis bahia): 0 limits, 3 violations of any kind, 0 effluent exceedances.
NOEC Sub-Lethal Static Renewal 7 Day Chronic Americamysis bahia (formerly Mysidopsis bahia): 0 limits, 3 violations of any kind, 0 effluent exceedances.
NOEC Sub-Lethal Static Renewal 7 Day Chronic Menidia menidia: 0 limits, 3 violations of any kind, 0 effluent exceedances.
Low Flow Pass/Fail Survival Test Static Renewal 7 Day Chronic Pimephales promelas: 2 limits, 2 violations of any kind, 0 effluent exceedances.
NOEC Lethal Static Renewal 7 Day Chronic Pimephales promelas: 2 limits, 2 violations of any kind, 0 effluent exceedances.
NOEC Sub-Lethal Static Renewal 7 Day Chronic Pimephales promelas: 2 limits, 2 violations of any kind, 0 effluent exceedances.
Pass/Fail Sub-Lethal Static Renewal 7 Day Chronic Pinephales promelas: 2 limits, 2 violations of any kind, 0 effluent exceedances.
LOEC Lethal Survival Static Renewal 7 Day Chronic Pimephales promelas: 2 limits, 2 violations of any kind, 0 effluent exceedances.
LOEC Sub-Lethal Reproduction Static Renewal 7 Day Chronic Pimephales promelas: 2 limits, 2 violations of any kind, 0 effluent exceedances.
LC50 Pass/Fail Static 24Hr Acute Americamysis bahia (formerly Mysidopsis bahia): 0 limits, 2 violations of any kind, 0 effluent exceedances.
LC50 Pass/Fail Static 24Hr Acute Menidia menidia: 0 limits, 2 violations of any kind, 0 effluent exceedances.
Pass/Fail Sub-Lethal Static Renewal 7 Day Chronic Americamysis bahia (formerly Mysidopsis bahia): 0 limits, 2 violations of any kind, 0 effluent exceedances.
Pass/Fail Sub-Lethal Static Renewal 7 Day Chronic Menidia menidia: 0 limits, 2 violations of any kind, 0 effluent exceedances.
Whole effluent toxicity - retest #1: 3 limits, 1 violation of any kind, 0 effluent exceedances.
Whole effluent toxicity - retest #2: 3 limits, 1 violation of any kind, 0 effluent exceedances.
Polychlorinated biphenyls [PCBs]: 1 limit, 1 violation of any kind, 0 effluent exceedances.
Toxicity characteristic leaching procedure: 1 limit, 1 violation of any kind, 0 effluent exceedances.
Annual amount of sludge land applied: 1 limit, 1 violation of any kind, 0 effluent exceedances.
Annual amt. sludge disposed surface unit: 1 limit, 1 violation of any kind, 0 effluent exceedances.
Annual amt sludge transported interstate: 1 limit, 1 violation of any kind, 0 effluent exceedances.
Compliance w/part 258 sludge requirement: 1 limit, 1 violation of any kind, 0 effluent exceedances.
Whole Effluent Toxicity [WET] - C. dubia: 8 limits, 0 violations of any kind, 0 effluent exceedances.
Arsenic, dry weight: 5 limits, 0 violations of any kind, 0 effluent exceedances.
Chromium, sludge, total, dry weight [as Cr]: 5 limits, 0 violations of any kind, 0 effluent exceedances.
Selenium, dry weight: 3 limits, 0 violations of any kind, 0 effluent exceedances.
Copper, dry weight: 3 limits, 0 violations of any kind, 0 effluent exceedances.
Cadmium, dry weight: 3 limits, 0 violations of any kind, 0 effluent exceedances.
Molybdenum, sludge, total, dry weight [as Mo]: 3 limits, 0 violations of any kind, 0 effluent exceedances.
Zinc, sludge, total, dry weight [as Zn]: 3 limits, 0 violations of any kind, 0 effluent exceedances.
Lead, sludge, total, dry weight [as Pb]: 3 limits, 0 violations of any kind, 0 effluent exceedances.
Nickel, sludge, total, dry weight [as Ni]: 3 limits, 0 violations of any kind, 0 effluent exceedances.
Mercury, sludge, total, dry weight [as Hg]: 3 limits, 0 violations of any kind, 0 effluent exceedances.
Nickel, total [as Ni]: 2 limits, 0 violations of any kind, 0 effluent exceedances.
Level of pathogen requirements achieved: 2 limits, 0 violations of any kind, 0 effluent exceedances.
Description of pathogen option used: 2 limits, 0 violations of any kind, 0 effluent exceedances.
Vector attraction reduction alternative used: 2 limits, 0 violations of any kind, 0 effluent exceedances.

November 12, 2024: Permit Violations - Violation Specified in Comment (ST6).
March 29, 2023: Permit Violations - Violation Specified in Comment (ST6).
January 24, 2019: Permit Violations - Violation Specified in Comment (ST6).

Texas holds 1,720 Publicly owned treatment works coverages of this permit type in EPA’s file; 1,394 were issued before TX0024287.

Coverages issued nearest TX0024287

June 1, 2020: CITY OF GARLAND ROWLETT CREEK, Garland, TX0024686, held by GARLAND, CITY OF
June 1, 2020: HARRIS COUNTY MUD NO 539 WWTP, Katy, TX0139424, held by HARRIS COUNTY MUNICIPAL UTILITY DISTRICT NO. 539
June 3, 2020: CITY OF TAFT WWTF, Taft, TX0027472, held by TAFT, CITY OF
June 4, 2020: CITY OF NAVASOTA OLD WWTP, Navasota, TX0071790, held by NAVASOTA, CITY OF
June 4, 2020: GERONIMO CREEK WWTP, Seguin, TX0103535, held by SEGUIN, CITY OF
June 18, 2020: COTTONWOOD CREEK WWTP, Manor, TX0137448, held by MANOR, CITY OF
June 22, 2020: CITY OF COTULLA WWTP, Cotulla, TX0027499, held by COTULLA, CITY OF
June 25, 2020: ARANSAS COUNTY MUD 1 WWTP, Rockport, TX0128970, held by ARANSAS COUNTY MUD 1
July 2, 2020: CITY OF INGLESIDE WWTP, Ingleside, TX0020401, held by INGLESIDE, CITY OF
July 2, 2020: WINNIE - STOWELL WWTF, Winnie, TX0020460, held by TRINITY BAY CONSERVATION DISTRICT

NORTH MUSTANG ISLAND WWTP among its neighbors

Its county holds 317, 24 of them major permits; TX0024287 is a major permit.

Other permits in the county

18005A-21051 ALAMEDA ST FROM LOUISIANA AVE TO TEXAN TRAIL, Corpus Christi: TXR1506OJ, minor permit, discharging to THE DRAINAGE BASIN OUTFALLS INTO THE RECEIVING WAT, permit term to March 4, 2028
18156A SHIP CHANNEL WATERLINE & GAS LINE CROSSING, Corpus Christi: TXR1526PI, minor permit, discharging to CORPUS CHRISTI BAY, permit term to March 4, 2028
3L ENERGY SOLUTIONS, Corpus Christi: TXR05GK38, minor permit, permit term to August 13, 2026
AARON DR, Corpus Christi: TXR1521TT, minor permit, discharging to OSO CREEK BASIN, permit term to March 4, 2028
AEP MCKENZIE ROADSAXET SUBSTATIONS SITE PREPARATION, Corpus Christi: TXR1521XK, minor permit, discharging to OSO CREEK, permit term to March 4, 2028
AGUA DULCE COMPRESSOR STA, Banquete: TXR1514VQ, minor permit, discharging to PETRONILA CREEK, permit term to March 4, 2028
AGUA DULCE WWTF, Agua Dulce: TX0033367, minor permit, discharging to RAILROAD DITCH; AGUA DULCE CREEK, permit term to June 1, 2020
AIRPORT ROAD FROM HORNE ROAD TO MORGAN AVE, Corpus Christi: TXR1530PW, minor permit, discharging to CORPUS CHRISTI BAY, permit term to March 4, 2028
AL SPEIGHT MILITARY RAIL YARD, Corpus Christi: TXR1510RB, minor permit, discharging to CORPUS CHRISTI SHIP CHANNEL INNER HARBOR, permit term to March 4, 2028
AL SPEIGHT STORAGE YARD, Corpus Christi: TXR1503ZH, minor permit, discharging to CORPUS CHRISTI BAY, permit term to March 4, 2028

Identity

Facility as filed	NORTH MUSTANG ISLAND WWTP
Permittee as filed	NUECES COUNTY WCID 4
NPDES ID	TX0024287
Permit status	Administratively continued (past its expiration date and still in force until reissued)
Permit type	Individual permit
Discharger class	Major discharger
Facility type	Publicly owned treatment works
Program	Publicly owned treatment works
Issued	June 18, 2020
Expiration date	June 18, 2025
Address	Port Aransas, TX 78373
Receiving water	FW POND/MARSH;E FLATS PORTION OF CC BAY
SIC	4952 – Sewerage Systems

Effluent limits and exceedances

72Pollutants on file
55Under a numeric limit
45With a violation of any kind
6With an effluent exceedance

An effluent exceedance is a discharge monitoring report value over the permit’s numeric limit (EPA’s violation code E90). A violation of any kind also counts a report not filed. Each row is EPA’s own count for that pollutant; the 60 with the most exceedances of 72 are shown.

Pollutant or measure	Limits	Violations, any kind	Effluent exceedances	Latest exceedance	Largest exceedance, as filed
Solids, total suspended	3	19	7	July 31, 2021	135% over the limit
Enterococci	0	12	7	June 30, 2019	2,226% over the limit
Chlorine, total residual	2	11	3	September 30, 2010	550% over the limit
Nitrogen, ammonia total [as N]	3	11	2	February 28, 2021	100% over the limit
E. coli	2	2	2	April 30, 2023	105% over the limit
BOD, 5-day, 20 deg. C	0	4	1	March 31, 2003	40% over the limit
Flow, in conduit or thru treatment plant	4	31	0
Zinc, total [as Zn]	0	27	0
pH	3	9	0
BOD, carbonaceous [5 day, 20 C]	3	9	0
NOEC Lethal Static Renewal 7 Day Chronic Menidia menidia	0	5	0
Low Flow Pass/Fail Survival Test Static Renewal 7 Day Chronic Ceriodaphnia dubia	2	4	0
NOEC Lethal Static Renewal 7 Day Chronic Ceriodaphnia dubia	2	4	0
NOEC Sub-Lethal Static Renewal 7 Day Chronic Ceriodaphnia dubia	2	4	0
Pass/Fail Sub-Lethal Static Renewal 7 Day Chronic Ceriodaphnia dubia	2	4	0
LOEC Lethal Survival Static Renewal 7 Day Chronic Ceriodaphnia dubia	2	4	0
LOEC Sub-Lethal Reproduction Static Renewal 7 Day Chronic Ceriodaphnia dubia	2	4	0
Oxygen, dissolved [DO]	1	4	0
LOEC Lethal Survival Static Renewal 7 Day Chronic Americamysis bahia (formerly Mysidopsis bahia)	0	4	0
LOEC Lethal Survival Static Renewal 7 Day Chronic Menidia menidia	0	4	0
LOEC Sub-Lethal Reproduction Static Renewal 7 Day Chronic Americamysis bahia (Mysidopsis bahia)	0	4	0
LOEC Sub-Lethal Reproduction Static Renewal 7 Day Chronic Menidia menidia	0	4	0
Low Flow Pass/Fail Survival Test Static Renewal 7 Day Chronic Americamysis bahia (Mysidopsis bahia)	0	3	0
Low Flow Pass/Fail Survival Test Static Renewal 7 Day Chronic Menidia menidia	0	3	0
NOEC Lethal Static Renewal 7 Day Chronic Americamysis bahia (formerly Mysidopsis bahia)	0	3	0
NOEC Sub-Lethal Static Renewal 7 Day Chronic Americamysis bahia (formerly Mysidopsis bahia)	0	3	0
NOEC Sub-Lethal Static Renewal 7 Day Chronic Menidia menidia	0	3	0
Low Flow Pass/Fail Survival Test Static Renewal 7 Day Chronic Pimephales promelas	2	2	0
NOEC Lethal Static Renewal 7 Day Chronic Pimephales promelas	2	2	0
NOEC Sub-Lethal Static Renewal 7 Day Chronic Pimephales promelas	2	2	0
Pass/Fail Sub-Lethal Static Renewal 7 Day Chronic Pinephales promelas	2	2	0
LOEC Lethal Survival Static Renewal 7 Day Chronic Pimephales promelas	2	2	0
LOEC Sub-Lethal Reproduction Static Renewal 7 Day Chronic Pimephales promelas	2	2	0
LC50 Pass/Fail Static 24Hr Acute Americamysis bahia (formerly Mysidopsis bahia)	0	2	0
LC50 Pass/Fail Static 24Hr Acute Menidia menidia	0	2	0
Pass/Fail Sub-Lethal Static Renewal 7 Day Chronic Americamysis bahia (formerly Mysidopsis bahia)	0	2	0
Pass/Fail Sub-Lethal Static Renewal 7 Day Chronic Menidia menidia	0	2	0
Whole effluent toxicity - retest #1	3	1	0
Whole effluent toxicity - retest #2	3	1	0
Polychlorinated biphenyls [PCBs]	1	1	0
Toxicity characteristic leaching procedure	1	1	0
Annual amount of sludge land applied	1	1	0
Annual amt. sludge disposed surface unit	1	1	0
Annual amt sludge transported interstate	1	1	0
Compliance w/part 258 sludge requirement	1	1	0
Whole Effluent Toxicity [WET] - C. dubia	8	0	0
Arsenic, dry weight	5	0	0
Chromium, sludge, total, dry weight [as Cr]	5	0	0
Selenium, dry weight	3	0	0
Copper, dry weight	3	0	0
Cadmium, dry weight	3	0	0
Molybdenum, sludge, total, dry weight [as Mo]	3	0	0
Zinc, sludge, total, dry weight [as Zn]	3	0	0
Lead, sludge, total, dry weight [as Pb]	3	0	0
Nickel, sludge, total, dry weight [as Ni]	3	0	0
Mercury, sludge, total, dry weight [as Hg]	3	0	0
Nickel, total [as Ni]	2	0	0
Level of pathogen requirements achieved	2	0	0
Description of pathogen option used	2	0	0
Vector attraction reduction alternative used	2	0	0

Inspections, violations and enforcement

3Single-event violations

Date	What EPA recorded	Agency
November 12, 2024	Permit Violations - Violation Specified in Comment	ST6
March 29, 2023	Permit Violations - Violation Specified in Comment	ST6
January 24, 2019	Permit Violations - Violation Specified in Comment	ST6

Inspections

EPA’s inspection file holds no inspection for NPDES TX0024287.

Formal enforcement and penalties

0 formal actions, 0 of them with a penalty assessed. Federal and state penalties are separate figures from separate authorities and are shown as each was filed, never added together.

Informal enforcement

EPA’s informal enforcement file holds no action for NPDES TX0024287.

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Figures from EPA’s ICIS-NPDES download, loaded October 14, 2026.

This public-records page covers Clean Water Act discharge permit NPDES TX0024287 for the NORTH MUSTANG ISLAND WWTP in Port Aransas, TX, held by NUECES COUNTY WCID 4, with an administratively continued status and a Major Discharger class. The page lists 55 for permit-status figures, 6 pollutants under a numeric limit, and 6 pollutants with an effluent exceedance.