Winterhaven Water Development, AZ
Lead reported as not detected
Latest 90th-percentile lead: reported as 0 (not detected) (monitoring period 2024-2026). The federal action level is 15 ppb today and drops to 10 ppb in Nov 2027; EPA's health goal is 0. The latest 90th-percentile result was reported as 0 (not detected at the lab's limit). That says the sampled homes were low, not that your home has no lead service line. Check your utility's service line inventory for your address.
Who runs the water here
Winterhaven Water Development serves about 685 people through 274 service connections, which makes it a small system under EPA's size classes. It is privately owned and draws groundwater, in Pima County, Arizona. EPA system ID: AZ0410119; phone on file: 520-327-0111. Ask them for your address in their service line inventory - every system had to publish one by Oct 2024.
Every lead result on file
Against the period ending 2023 (0 ppb) the latest result is about the same. The highest 90th-percentile result EPA holds for Winterhaven Water Development is 0.64 ppb across 5 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2026 | 0 (not detected) |
| 2023 | 0 (not detected) |
| 2020 | 0 (not detected) |
| 2017 | 0 (not detected) |
| 2017 | 0.64 ppb |
Against other Arizona systems
Of the 730 Arizona systems with a lead result, the median latest reading is 0 ppb; 9 are over 15 ppb right now and 58 have gone over at some point. Winterhaven Water Development's reported as 0 (not detected) sits at the 40th percentile in Arizona and the 24th nationally (higher means more lead). Systems reporting 0 tie at the bottom, so the rank mostly reflects size among them.
Neighbouring systems
137 other systems share Pima County; 44 of them have a higher latest lead result than Winterhaven Water Development. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Tucson City Of | 732,906 | 0.65 ppb |
| Metropolitan Dwid | 45,570 | 0.57 ppb |
| Oro Valley Water Utility | 42,316 | 1 ppb |
| Community Wc Of Green Valley | 22,085 | 0 (not detected) |
| Usaf Davis Monthan Afb | 18,640 | 0 (not detected) |
| Sahuarita Water Company | 18,178 | 0 (not detected) |
| Vail Water Company | 17,500 | 0 (not detected) |
| Flowing Wells Irrigation District | 16,000 | 0 (not detected) |
| Marana Municipal - Marana | 15,162 | 0 (not detected) |
| Tucson Water Corona De Tucson | 10,217 | 0.78 ppb |
Next steps for Tucson, AZ
Look up your address in Winterhaven Water Development's service line inventory. If it says lead, galvanized or unknown, test your tap. If your own line is lead, replacing the private side runs about $1,200-$12,300 (EPA average about $4,700). Ask Winterhaven Water Development whether it covers that cost before hiring anyone - many utilities now do.
These figures describe homes the utility sampled, not your tap. Only your service line record or a test of your own water answers the question for your house. The lead result guide covers how utilities pick the homes they sample. A zero today does not rule out a jump later - the rules are tightening in 2027.