Clean Water Act discharge permit · NPDES AZ0020001
PIMA COUNTY - TRES RIOS WWRF, Tucson, AZ: NPDES AZ0020001 discharge permit, effluent exceedances, inspections, penalties
- EffectivePermit status
- MajorDischarger class
- 175Pollutants under a numeric limit
- 6Pollutants with an effluent exceedance
PIMA COUNTY - TRES RIOS WWRF, held by Pima County - Regional Wastewater Reclamation Department, holds NPDES permit AZ0020001. EPA’s file records it issued May 3, 2019 and expiring July 9, 2022. The status and dates are as EPA’s permit file stood when Velarion loaded it (September 14, 2026); EPA’s free Detailed Facility Report on ECHO carries the permit’s current standing.
Identity
| Facility as filed | PIMA COUNTY - TRES RIOS WWRF |
|---|---|
| Permittee as filed | Pima County - Regional Wastewater Reclamation Department |
| NPDES ID | AZ0020001 |
| Permit status | Effective |
| Permit type | Individual permit |
| Discharger class | Major discharger |
| Facility type | Publicly owned treatment works |
| Program | Publicly owned treatment works |
| Issued | May 3, 2019 |
| Expiration date | July 9, 2022 |
| Address | Tucson, AZ 85743 |
| Receiving water impaired | 303(D) Listed |
| Subwatershed | Ruelas Canyon-Santa Cruz River (HUC 150503010908) |
Cited to the EPA ICIS-NPDES permit file (ECHO download).
Effluent limits and exceedances
- 179Pollutants on file
- 175Under a numeric limit
- 165With 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 179 are shown.
| Pollutant or measure | Limits | Violations, any kind | Effluent exceedances | Latest exceedance | Largest exceedance, as filed |
|---|---|---|---|---|---|
| Chlorine, total residual | 5 | 30 | 23 | November 30, 2012 | 30,900% over the limit |
| E. coli, colony forming units [CFU] | 3 | 11 | 8 | April 30, 2013 | 320% over the limit |
| Cyanide, total [as CN] | 5 | 18 | 7 | August 31, 2024 | 571% over the limit |
| Nitrogen, ammonia total [as N] | 3 | 7 | 5 | October 31, 2025 | 148% over the limit |
| Di[2-ethylhexyl] phthalate [DEHP] | 1 | 20 | 4 | September 30, 2006 | 333% over the limit |
| pH | 4 | 12 | 2 | February 28, 2014 | |
| Copper, total recoverable | 1 | 29 | 0 | ||
| Solids, total suspended | 7 | 19 | 0 | ||
| BOD, 5-day, 20 deg. C | 7 | 17 | 0 | ||
| Silver total recoverable | 5 | 17 | 0 | ||
| Lead, total recoverable | 1 | 17 | 0 | ||
| Chromium, hexavalent dissolved [as Cr] | 1 | 13 | 0 | ||
| Oil & Grease | 2 | 9 | 0 | ||
| TU Static Renewal 7-Day Chronic Pimphales promelas | 3 | 7 | 0 | ||
| 1,2-Dichloropropane | 1 | 7 | 0 | ||
| Hardness, total [as CaCO3] | 3 | 6 | 0 | ||
| Flow, in conduit or thru treatment plant | 2 | 6 | 0 | ||
| Selenium, total recoverable | 1 | 5 | 0 | ||
| Mercury, total recoverable | 2 | 4 | 0 | ||
| Nitrogen, Kjeldahl, total [as N] | 1 | 4 | 0 | ||
| Nitrite + Nitrate total [as N] | 1 | 4 | 0 | ||
| Phosphorus, total [as P] | 1 | 4 | 0 | ||
| Beryllium, total recoverable [as Be] | 1 | 4 | 0 | ||
| Nickel, total recoverable | 1 | 4 | 0 | ||
| Zinc, total recoverable | 1 | 4 | 0 | ||
| Solids, total dissolved | 1 | 4 | 0 | ||
| Chromium, total recoverable | 0 | 4 | 0 | ||
| Antimony, total recoverable | 1 | 3 | 0 | ||
| Cadmium, dissolved [as Cd] | 0 | 3 | 0 | ||
| Temperature, water deg. centigrade | 3 | 2 | 0 | ||
| Sulfide, total [as S] | 3 | 2 | 0 | ||
| TU Static 4 Day Chronic Raphidocelis subcapitata (formerly Selenastrum capricornutum) | 3 | 2 | 0 | ||
| TU Static Renewal 7-Day Chronic Ceriodaphnia dubia | 3 | 2 | 0 | ||
| Oxygen, dissolved [DO] | 1 | 2 | 0 | ||
| 2-Methyl-4,6-dinitrophenol | 1 | 2 | 0 | ||
| Diquat | 1 | 2 | 0 | ||
| Dichlorobromomethane | 1 | 2 | 0 | ||
| Carbon tetrachloride | 1 | 2 | 0 | ||
| Dibromochloromethane | 1 | 2 | 0 | ||
| Toluene | 1 | 2 | 0 | ||
| Benzene | 1 | 2 | 0 | ||
| .delta.-BHC | 1 | 2 | 0 | ||
| Acenaphthylene | 1 | 2 | 0 | ||
| Acenaphthene | 1 | 2 | 0 | ||
| Acrolein | 1 | 2 | 0 | ||
| Acrylonitrile | 1 | 2 | 0 | ||
| Anthracene | 1 | 2 | 0 | ||
| Benzo[b]fluoranthene | 1 | 2 | 0 | ||
| Benzo[k]fluoranthene | 1 | 2 | 0 | ||
| Benzo[a]pyrene | 1 | 2 | 0 | ||
| Bis[2-chloroethyl] ether | 1 | 2 | 0 | ||
| Bis[2-chloroethoxy]methane | 1 | 2 | 0 | ||
| Bis[2-chloroisopropyl] ether | 1 | 2 | 0 | ||
| Butyl benzyl phthalate | 1 | 2 | 0 | ||
| Chlorobenzene | 1 | 2 | 0 | ||
| Chrysene | 1 | 2 | 0 | ||
| Diethyl phthalate | 1 | 2 | 0 | ||
| Dimethyl phthalate | 1 | 2 | 0 | ||
| 1,2-Diphenylhydrazine | 1 | 2 | 0 | ||
| Endrin aldehyde | 1 | 2 | 0 |
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
- 0Single-event violations
EPA’s single-event violation file, as loaded, holds no violation for NPDES AZ0020001.
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.
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Figures from EPA’s ICIS-NPDES download, loaded September 14, 2026.