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Clean Water Act discharge permit · NPDES TX0100170

DAYTON SOUTHWEST WWTP, Dayton, TX: NPDES TX0100170 discharge permit, effluent exceedances, inspections, penalties

DAYTON SOUTHWEST WWTP, held by CITY OF DAYTON, holds NPDES permit TX0100170, which discharges to Drainage Ditch, Unnamed Trib Linney. EPA’s file records it issued July 10, 2020 and expiring July 10, 2025. The status and dates are as EPA’s permit file stood when Velarion loaded it (October 14, 2026); EPA’s free Detailed Facility Report on ECHO carries the permit’s current standing.

Identity

Facility as filedDAYTON SOUTHWEST WWTP
Permittee as filedCITY OF DAYTON
NPDES IDTX0100170
Permit statusEffective
Permit typeIndividual permit
Discharger classMajor discharger
Facility typePublicly owned treatment works
ProgramPublicly owned treatment works
IssuedJuly 10, 2020
Expiration dateJuly 10, 2025
AddressDayton, TX 77535
Receiving waterDRAINAGE DITCH, UNNAMED TRIB LINNEY
SubwatershedWest Prong Old River (HUC 120302030302)
SIC4952 – Sewerage Systems

Cited to the EPA ICIS-NPDES permit file (ECHO download) and EPA’s NAICS/SIC and component files, the same download.

Effluent limits and exceedances

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 measureLimitsViolations, any kindEffluent exceedancesLatest exceedanceLargest exceedance, as filed
Flow, in conduit or thru treatment plant48765June 30, 202638,975% over the limit
Solids, total suspended33517June 30, 2026747% over the limit
E. coli2117March 31, 20261,113% over the limit
Whole effluent toxicity022December 31, 2009100% over the limit
BOD, carbonaceous [5 day, 20 C]3191July 31, 200320% over the limit
Chlorine, total residual2131December 31, 2003900% over the limit
Nitrogen, ammonia total [as N]3180
pH2140
Low Flow Pass/Fail Survival Test Static Renewal 7 Day Chronic Ceriodaphnia dubia280
Low Flow Pass/Fail Survival Test Static Renewal 7 Day Chronic Pimephales promelas280
NOEC Lethal Static Renewal 7 Day Chronic Pimephales promelas280
NOEC Sub-Lethal Static Renewal 7 Day Chronic Pimephales promelas280
Pass/Fail Sub-Lethal Static Renewal 7 Day Chronic Ceriodaphnia dubia280
Pass/Fail Sub-Lethal Static Renewal 7 Day Chronic Pinephales promelas280
LOEC Lethal Survival Static Renewal 7 Day Chronic Pimephales promelas280
LOEC Sub-Lethal Reproduction Static Renewal 7 Day Chronic Pimephales promelas280
Oxygen, dissolved [DO]170
Whole Effluent Toxicity [WET] - P. promelas460
NOEC Lethal Static Renewal 7 Day Chronic Ceriodaphnia dubia260
NOEC Sub-Lethal Static Renewal 7 Day Chronic Ceriodaphnia dubia260
LOEC Lethal Survival Static Renewal 7 Day Chronic Ceriodaphnia dubia260
LOEC Sub-Lethal Reproduction Static Renewal 7 Day Chronic Ceriodaphnia dubia260
LC50 Pass/Fail Static 24Hr Acute D. Pulex130
LC50 Pass/Fail Static 24Hr Acute Pimephales promelas130
Polychlorinated biphenyls [PCBs]010
Toxicity characteristic leaching procedure010
Ann. amt sludge disposed by other method010
Annual amt of sludge incinerated010
Annual sludge production, total010
Annual amount of sludge land applied010
Annual amt. sludge disposed surface unit010
Annual amt sludge disposed in landfill010
Annual amt sludge transported interstate010
Compliance w/part 258 sludge requirement010
Whole effluent toxicity - retest #1300
Whole effluent toxicity - retest #2300

Cited to the EPA ICIS-NPDES limits and effluent violations files (ECHO download); up to 60 rows shown, most exceedances first.

Inspections, violations and enforcement

DateWhat EPA recordedAgency
July 1, 2026Permit Violations - Violation Specified in CommentST6
May 20, 2026Permit Violations - Violation Specified in CommentST6
April 9, 2026Permit Violations - Violation Specified in CommentST6
July 8, 2025Permit Violations - Violation Specified in CommentST6
September 18, 2023Permit Violations - Violation Specified in CommentST6
August 9, 2022Permit Violations - Violation Specified in CommentST6

Velarion’s copy of EPA’s ICIS-NPDES files does not include the inspections, formal enforcement actions and informal enforcement actions files, so this page shows none of them. EPA’s free Detailed Facility Report on ECHO lists this permit’s inspections, enforcement actions and penalties.

Cited to the EPA ICIS-NPDES violation, inspection and enforcement files (ECHO download); up to 50 rows of each shown, newest first.

Watch this permit

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EPA publishes a free Detailed Facility Report for every permit on ECHO: its compliance status quarter by quarter, its inspections, and its enforcement actions and penalties. EPA also sends free notices of new inspections and enforcement actions through ECHO Notify; enter NPDES ID TX0100170 there.

Nearby on the register

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

What this page shows

This public-records page covers NPDES permit TX0100170 for the Dayton Southwest WWTP in Dayton, TX, held by the City of Dayton and discharging to Drainage Ditch, Unnamed Trib Linney within the West Prong Old River subwatershed (HUC 120302030302). The facts list 36 pollutants on file, 25 under a numeric limit, 34 with a violation of any kind, and 6 with an effluent exceedance.