Clean Water Act discharge permit · NPDES TX0139424

HARRIS COUNTY MUD NO 539 WWTP, Katy, TX: NPDES TX0139424 discharge permit, effluent exceedances, inspections, penalties

Administratively continuedPermit status
MinorDischarger class
8Pollutants under a numeric limit
2Pollutants with an effluent exceedance
0Inspections on file
0Formal enforcement actions

HARRIS COUNTY MUD NO 539 WWTP, held by HARRIS COUNTY MUNICIPAL UTILITY DISTRICT NO. 539, holds NPDES permit TX0139424, which discharges to Buffalo Bayou Above Tidal. EPA’s file records it issued June 1, 2020 and expiring May 31, 2025.

HARRIS COUNTY MUD NO 539 WWTP, Katy, Texas: Individual permit TX0139424, held by HARRIS COUNTY MUNICIPAL UTILITY DISTRICT NO. 539; Publicly owned treatment works; Administratively continued (past its expiration date and still in force until reissued); issued June 1, 2020, term to May 31, 2025; discharges to Buffalo Bayou Above Tidal.

Solids, total suspended: 3 limits, 1 violation of any kind, 1 effluent exceedance, latest January 31, 2026, largest 27% over the limit.
E. coli: 2 limits, 1 violation of any kind, 1 effluent exceedance, latest July 31, 2025, largest 36% over the limit.
Nitrogen, ammonia total [as N]: 3 limits, 0 violations of any kind, 0 effluent exceedances.
BOD, carbonaceous [5 day, 20 C]: 3 limits, 0 violations of any kind, 0 effluent exceedances.
pH: 2 limits, 0 violations of any kind, 0 effluent exceedances.
Flow, in conduit or thru treatment plant: 2 limits, 0 violations of any kind, 0 effluent exceedances.
Chlorine, total residual: 2 limits, 0 violations of any kind, 0 effluent exceedances.
Oxygen, dissolved [DO]: 1 limit, 0 violations of any kind, 0 effluent exceedances.

Texas holds 1,720 Publicly owned treatment works coverages of this permit type in EPA’s file; 1,389 were issued before TX0139424.

Coverages issued nearest TX0139424

May 26, 2020: HARRIS COUNTY MUD NO 560 WWTP, Crosby, TX0139513, held by HARRIS COUNTY MUNICIPAL UTILITY DISTRICT 560
May 28, 2020: GATESVILLE REGIONAL WTP, Gatesville, TX0137677, held by GATESVILLE, CITY OF
May 29, 2020: MCCRAY MEADOWS WWTP, Richmond, TX0135305, held by FORT BEND COUNTY MUD 143
May 29, 2020: HARLAN RD WTP, Navasota, TX0137561, held by WELLBORN SPECIAL UTILTIY DISTRICT
June 1, 2020: CITY OF GARLAND ROWLETT CREEK, Garland, TX0024686, held by GARLAND, CITY OF
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: NORTH MUSTANG ISLAND WWTP, Port Aransas, TX0024287, held by NUECES COUNTY WCID 4
June 18, 2020: COTTONWOOD CREEK WWTP, Manor, TX0137448, held by MANOR, CITY OF

HARRIS COUNTY MUD NO 539 WWTP among its neighbors

EPA’s permit file holds 116 discharge permits in the South Mayde Creek subwatershed (HUC 120401040203), TX0139424 among them. Its county holds 4,455, 195 of them major permits; TX0139424 is a minor permit.

Other permits in the South Mayde Creek subwatershed (HUC 120401040203)

ACCUMULATORS, Houston: TXRNEBZ28, minor permit, permit term to August 13, 2026
ADDICKS UD WWTP, Houston: TX0112585, minor permit, discharging to HCFCDD U101-20-00, SOUTH MAYDE CREE, permit term to April 1, 2022
ANNISTON, Katy: TXR1523SC, minor permit, discharging to BEAR CREEK 1014A, permit term to March 4, 2028
ANNISTON, Katy: TXR1530VA, minor permit, discharging to BEAR CREEK 1014A, permit term to March 4, 2028
ANNISTON, Katy: TXR1545WM, minor permit, discharging to BEAR CREEK 1014A, permit term to March 4, 2028
ANNISTON, Houston: TXR1556TK, minor permit, discharging to BEAR CREEK 1014A, permit term to March 4, 2028
ANNISTON, Houston: TXR1563PV, minor permit, discharging to BEAR CREEK 1014A, permit term to March 4, 2028
ANNISTON, Houston: TXR1564PV, minor permit, discharging to BEAR CREEK 1014A, permit term to March 4, 2028
ANNISTON, Houston: TXR1566SE, minor permit, discharging to BEAR CREEK 1014A, permit term to March 4, 2028
ANNISTON, Houston: TXR1582MB, minor permit, discharging to BEAR CREEK 1014A, permit term to March 4, 2028

Identity

Facility as filed	HARRIS COUNTY MUD NO 539 WWTP
Permittee as filed	HARRIS COUNTY MUNICIPAL UTILITY DISTRICT NO. 539
NPDES ID	TX0139424
Permit status	Administratively continued (past its expiration date and still in force until reissued)
Permit type	Individual permit
Discharger class	Minor discharger
Facility type	Publicly owned treatment works
Program	Publicly owned treatment works
Issued	June 1, 2020
Expiration date	May 31, 2025
Address	Katy, TX 77493
Receiving water	Buffalo Bayou Above Tidal
Subwatershed	South Mayde Creek (HUC 120401040203)

Effluent limits and exceedances

8Pollutants on file
8Under a numeric limit
2With a violation of any kind
2With 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.

Pollutant or measure	Limits	Violations, any kind	Effluent exceedances	Latest exceedance	Largest exceedance, as filed
Solids, total suspended	3	1	1	January 31, 2026	27% over the limit
E. coli	2	1	1	July 31, 2025	36% over the limit
Nitrogen, ammonia total [as N]	3	0	0
BOD, carbonaceous [5 day, 20 C]	3	0	0
pH	2	0	0
Flow, in conduit or thru treatment plant	2	0	0
Chlorine, total residual	2	0	0
Oxygen, dissolved [DO]	1	0	0

Inspections, violations and enforcement

0Single-event violations

EPA’s single-event violation file, as loaded, holds no violation for NPDES TX0139424.

Inspections

EPA’s inspection file holds no inspection for NPDES TX0139424.

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 TX0139424.

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Figures from EPA’s ICIS-NPDES download, loaded September 15, 2026.

This public-records page covers NPDES permit TX0139424 for the HARRIS COUNTY MUD NO 539 WWTP in Katy, TX, held by HARRIS COUNTY MUNICIPAL UTILITY DISTRICT NO. 539, which discharges to Buffalo Bayou Above Tidal in the South Mayde Creek subwatershed (HUC 120401040203). The permit is listed as administratively continued, with a Minor discharger class and 8 pollutants under a numeric limit, 2 of which show an effluent exceedance.