Wastewater treatment plants in Arizona
56 facilities · 185 MGD combined flow
Klarifi tracks 56 publicly owned wastewater treatment plants in Arizona with a combined average flow of 185 MGD, serving about 2,882,159 residents. 15 plants treat more than 1 MGD and 3 more than 10 MGD; 25 use lagoon systems and 15 have digesters or biogas infrastructure. The largest is 91st Avenue WWTP in Tolleson at 83.69 MGD. 8 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.
56 plant locations in Arizona; dot size follows average flow. Boundaries: U.S. Census Bureau.
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 | 83.69 | 230 | AZ0020524 | Apr 2028 | 2 |
| 23rd Avenue Wastewater Treatment Plant | Phoenix | 35.19 | 63 | AZ0020559 | Jun 2029 | 2 |
| Pima County - Ina Road WWTP | Tucson | 29.75 | 50 | AZ0020001 | May 2027 | 3 |
| Yuma, City Of - Figueroa Ave WPCF | Yuma | 7.28 | 12 | AZ0020443 | Aug 2028 | 13 |
| Northwest Water Reclamation Plant | Mesa | 3.08 | 18 | AZ0024627 | Jun 2024 | 0 |
| Goodyear, City Of - 157th Ave WWTP | Goodyear | 2.9 | 7.5 | AZ0022357 | Mar 2027 | 1 |
| Town Of Prescott Valley - WWTP | Prescott Valley | 2.69 | 3.75 | AZ0025381 | Feb 2027 | 0 |
| Rio De Flag WWTP | Flagstaff | 2.15 | 4 | AZ0023639 | Apr 2030 | 4 |
| Town Of Buckeye - Sundance Wwrf | Buckeye | 2.13 | 6 | AZ0024881 | Apr 2029 | 42 |
| Tolleson WWTP | Tolleson | 2.1 | 17.5 | AZ0020338 | Feb 2031 | 28 |
Treatment technology for each plant is shown with a free Klarifi account. Create one →
Arizona plants by treatment technology
All 56 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 October 26, 2026.
Wastewater terms: WWTP · POTW · MGD · NPDES permit · Ozonation · Activated sludge · all terms
Cite this page
Journalists, researchers and educators are welcome to quote these figures. Please credit Klarifi as the source and link to this page.
Klarifi. “Wastewater treatment plants in Arizona.” Updated October 26, 2026. https://klarifi.io/facilities/arizonaNeed a custom cut of the data for a state, a county or a list of plants? Email info@klarifi.io.