91st Avenue WWTP
5615 S 91st Ave, Tolleson, AZ 85353 · Maricopa County · Publicly Owned Treatment Works
- Average flow
- 83.69 MGD
- Design flow
- 230 MGD
- NPDES permit
- AZ0020524
- Effective
- Permit expires
- April 2028
- Population served
- —
- CWNS 2022
91st Avenue WWTP is a publicly owned wastewater treatment works in Tolleson, Maricopa County, Arizona treating an average of 83.69 million gallons per day against a permitted design capacity of 230 MGD. It discharges under NPDES permit AZ0020524 (effective), which expires in April 2028, with 2 recorded violations in the last three years. EPA has recorded 2 formal enforcement actions naming the plant, the latest in February 1992.
Treatment technology
4 treatment structures and unit processes identified at 91st Avenue WWTP.
Available with a free Klarifi account
See the full treatment train at 91st Avenue WWTP: structures, unit processes and planned upgrades, with exact unit counts.
Compliance snapshot (last 3 years)
- Total violations
- 2
- Effluent violations
- 2
Based on NPDES Discharge Monitoring Reports. Full violation history, parameters and discharge data available in the Klarifi platform.
EPA enforcement history
Federal civil enforcement cases, compliance inspections and informal actions recorded for 91st Avenue WWTP in EPA's ICIS system.
- Formal actions
- 2
- 0 since FY2020
- Penalties assessed
- $450,000
- all cases
- EPA inspections
- 0
- none on record
Latest case · Feb 1992
PHOENIX, CITY OF
Judicial case · CWA, Clean Water Act · Final Order With Penalty · Penalty $450,000 · The case also names 1 other plant, and its amounts cover all of them
Source: EPA ECHO, civil enforcement case 09-1989-0021.
Full case history with a free Klarifi account
Every action against 91st Avenue WWTP with dates, milestones, violation types and EPA's complete case summaries, plus inspections and informal actions.
Key contacts
3 verified contacts for 91st Avenue WWTP, with validated emails and direct phone numbers.
Unlock 3 verified contacts
Names, validated emails and direct phone numbers for decision-makers at 91st Avenue WWTP, plus the full compliance history and discharge data.
Nearby wastewater treatment plants in Arizona
Tolleson · 3 mi away
2.1 MGD
Phoenix · 8 mi away
35.19 MGD
Goodyear · 9 mi away
2.9 MGD
Phoenix · 10 mi away
0.24 MGD
Goodyear · 12 mi away
—
Goodyear · 14 mi away
0.11 MGD
Buckeye · 16 mi away
2.13 MGD
Buckeye · 20 mi away
0.22 MGD
91st Avenue WWTP: frequently asked questions
Sources and methodology
Flow, permit and violation figures come from the EPA's ICIS-NPDES discharge monitoring records. Population served comes from the Clean Watersheds Needs Survey 2022. Treatment structures are identified by Klarifi's review of aerial imagery, and capital improvement projects are extracted from published municipal budget documents. Violations are counted over the last three years of monitoring reports.
Data refreshed October 26, 2026; facility record last updated September 12, 2026.
Wastewater terms: POTW · MGD · NPDES permit · Inflow and infiltration · Anaerobic digester · Lift station · all terms