Wastewater treatment plants in Arizona
53 facilities · 171 MGD combined flow
Klarifi tracks 53 publicly owned wastewater treatment plants in Arizona with a combined average flow of 171 MGD, serving about 2,799,438 residents. 11 plants treat more than 1 MGD and 3 more than 10 MGD; 25 use lagoon systems and 13 have digesters or biogas infrastructure. The largest is 91st Avenue WWTP in Tolleson at 78.71 MGD. 9 NPDES permits expire this year and 12 next year.
Every plant below links to a profile with average and design flow, the NPDES permit and its expiry, a three-year compliance snapshot and the capital projects planned in its city. Treatment technology and verified contacts are shown with a free Klarifi account.
53 plant locations in Arizona; dot size follows average flow.
NPDES permits and renewals in Arizona
Every plant discharges under an NPDES permit that is renewed every five years, usually with tighter limits. The renewal year is the year a plant budgets for upgrades.
Largest wastewater treatment plants in Arizona
| Facility | City | Avg flow (MGD) | Design (MGD) | NPDES permit | Expires | Violations (3y) |
|---|---|---|---|---|---|---|
| 91st Avenue WWTP | Tolleson | 78.71 | 230 | AZ0020524 | Apr 2028 | 2 |
| 23rd Avenue Wastewater Treatment Plant | Phoenix | 35.67 | 63 | AZ0020559 | Jun 2029 | 2 |
| Pima County - Ina Road WWTP | Tucson | 31.89 | 50 | AZ0020001 | May 2027 | 3 |
| Casa Grande WRF | Casa Grande | 3.54 | 14 | AZ0025178 | Sep 2029 | 29 |
| Town Of Prescott Valley - WWTP | Prescott Valley | 2.74 | 3.75 | AZ0025381 | Feb 2027 | 0 |
| Northwest Wrp | Mesa | 2.72 | 18 | AZ0024031 | Nov 2029 | 6 |
| Goodyear, City Of - 157th Ave WWTP | Goodyear | 2.5 | 7.5 | AZ0022357 | Mar 2027 | 1 |
| Town Of Buckeye - Sundance Wwrf | Buckeye | 2.02 | 6 | AZ0024881 | Apr 2029 | 37 |
| Kayenta WWTF | Kayenta | 1.46 | 0.9 | NN0020281 | Jan 2029 | 144 |
| Buckeye WWTP | Buckeye | 1.38 | 4.5 | AZ0025313 | Oct 2030 | 1 |
Treatment technology for each plant is shown with a free Klarifi account. Create one →
Arizona plants by treatment technology
All 53 plants in Arizona
Wastewater treatment in Arizona: 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 September 21, 2026.