The 40 largest wastewater treatment plants in Arizona
Ranked by average flow · 185 MGD combined · 100% of the state's reported flow
91st Avenue WWTP in Tolleson is the largest publicly owned wastewater treatment plant in Arizona by reported average flow, treating about 83.69 million gallons per day. The 40 plants below treat 185 MGD between them, 100% of the flow reported by all 56 plants in the state, and serve about 2,369,359 people. Every plant links to its profile with permit and compliance data. Treatment technology is shown with a free Klarifi account.
| # | Facility | City | Avg flow (MGD) | Population | NPDES permit | Expires | Violations (3y) |
|---|---|---|---|---|---|---|---|
| 1 | 91st Avenue WWTP | Tolleson | 83.69 | — | AZ0020524 | Apr 2028 | 2 |
| 2 | 23rd Avenue Wastewater Treatment Plant | Phoenix | 35.19 | 1,604,039 | AZ0020559 | Jun 2029 | 2 |
| 3 | Pima County - Ina Road WWTP | Tucson | 29.75 | 400,657 | AZ0020001 | May 2027 | 3 |
| 4 | Yuma, City Of - Figueroa Ave WPCF | Yuma | 7.28 | 82,721 | AZ0020443 | Aug 2028 | 13 |
| 5 | Northwest Water Reclamation Plant | Mesa | 3.08 | — | AZ0024627 | Jun 2024 | 0 |
| 6 | Goodyear, City Of - 157th Ave WWTP | Goodyear | 2.9 | 80,313 | AZ0022357 | Mar 2027 | 1 |
| 7 | Town Of Prescott Valley - WWTP | Prescott Valley | 2.69 | 55,332 | AZ0025381 | Feb 2027 | 0 |
| 8 | Rio De Flag WWTP | Flagstaff | 2.15 | 26,185 | AZ0023639 | Apr 2030 | 4 |
| 9 | Town Of Buckeye - Sundance Wwrf | Buckeye | 2.13 | — | AZ0024881 | Apr 2029 | 42 |
| 10 | Tolleson WWTP | Tolleson | 2.1 | 7,332 | AZ0020338 | Feb 2031 | 28 |
| 11 | Buckeye WWTP | Buckeye | 1.91 | 45,732 | AZ0025313 | Oct 2030 | 1 |
| 12 | Northwest Wrp | Mesa | 1.33 | — | AZ0024031 | Nov 2029 | 6 |
| 13 | Tucson Airport Remediation Project - Co-Mingled Plume | Tucson | 1.15 | — | AZ0026417 | Oct 2026 | 0 |
| 14 | City Of Mesa - Greenfield Water Reclamation Plant | Gilbert | 1.08 | — | AZ0025241 | Sep 2029 | 0 |
| 15 | Cottonwood WWTF | Cottonwood | 1.02 | 10,540 | AZ0024716 | Apr 2027 | 17 |
| 16 | American Gulch Wastewater Treatment Plant | Payson | 0.79 | 16,805 | AZ0020117 | Apr 2027 | 0 |
| 17 | City Of Somerton - WWTP | Somerton | 0.74 | — | AZ0026603 | Dec 2029 | 0 |
| 18 | City Of Safford - Gila Resources Wrp | Safford | 0.72 | 11,900 | AZ0024911 | Jun 2029 | 0 |
| 19 | Whiteriver Sewage Lagoon | Whiteriver | 0.58 | — | AZ0024058 | Oct 2026 | 481 |
| 20 | Pinal Creek WWTP | Globe | 0.53 | 8,727 | AZ0020249 | Mar 2031 | 9 |
| 21 | Joint Venture WWTF | Parker | 0.48 | 5,602 | AZ0021415 | Nov 2026 | 165 |
| 22 | Tuba City WWTP | Tuba City | 0.44 | — | NN0020290 | Apr 2027 | 138 |
| 23 | City Of Peoria | Peoria | 0.43 | — | AZ0024945 | Jul 2027 | 17 |
| 24 | Window Rock Wastewater Treatment Facility | Fort Defiance | 0.4 | — | NN0021555 | Sep 2026 | 15 |
| 25 | Kayenta WWTF | Kayenta | 0.26 | — | NN0020281 | Jan 2029 | 142 |
| 26 | City Of Phoenix - Rio Salado Habitat Restoration | Phoenix | 0.24 | — | AZ0024554 | Aug 2028 | 0 |
| 27 | Chinle WWTF | Chinle | 0.24 | — | NN0020265 | Aug 2031 | 160 |
| 28 | Town Of Gila Bend - WWTP | Gila Bend | 0.22 | 1,938 | AZ0020231 | Jun 2030 | 94 |
| 29 | Festival Ranch WRF | Buckeye | 0.22 | — | AZ0025216 | Oct 2028 | 3 |
| 30 | City Of Kingman - Downtown Pond | Kingman | 0.21 | 2,500 | AZ0026018 | Dec 2026 | 6 |
| 31 | Quartzsite, Town Of - WWTP | Quartzsite | 0.2 | — | AZ0023752 | Aug 2027 | 5 |
| 32 | Town Of Superior Wastewater Treatment Plant (wwtp) | Superior | 0.13 | 3,193 | AZ0021199 | Apr 2028 | 19 |
| 33 | Six Mile Lagoon Wastewater Treatment Facility | Peridot | 0.12 | — | AZ0024640 | Jun 2030 | 848 |
| 34 | City Of Goodyear - Rainbow Valley WRF | Goodyear | 0.11 | — | AZ0025135 | Apr 2029 | 0 |
| 35 | Yuma Main Street Treatment Plant | Yuma | 0.09 | — | AZ0025411 | May 2027 | 1 |
| 36 | Town Of Kearny Wastewater Reclamation Facility | Kearny | 0.09 | 2,185 | AZ0024449 | Jul 2026 | 46 |
| 37 | Tusayan Sanitary District | Grand Canyon | 0.07 | — | AZ0026719 | Aug 2027 | 0 |
| 38 | Town Of Patagonia - WWTP | Patagonia | 0.07 | 706 | AZ0025011 | Jul 2030 | 0 |
| 39 | City Of Tombstone - WWTP | Tombstone | 0.05 | 1,641 | AZ0025577 | Mar 2031 | 11 |
| 40 | Winkelman WWTP | Winkelman | 0.01 | 1,311 | AZ0020176 | May 2029 | 27 |
Treatment technology for each plant is shown with a free Klarifi account. Create one →
Largest plants 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 · Inflow and infiltration · Sludge dewatering · 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. “The 40 largest wastewater treatment plants in Arizona (2026).” Updated October 26, 2026. https://klarifi.io/facilities/arizona/largestNeed a custom cut of the data for a state, a county or a list of plants? Email info@klarifi.io.