Desert Oasis, AZ
Lead reported as not detected
Latest 90th-percentile lead: reported as 0 (not detected) (monitoring period 2022-2024). 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
Desert Oasis serves about 23,963 people through 8,123 service connections, which makes it a large system under EPA's size classes. It is owned by a local government (city, town, county or district) and draws groundwater, in Maricopa County, Arizona. EPA system ID: AZ0407523; phone on file: 623-222-7030. Ask them for your address in their service line inventory - every system had to publish one by Oct 2024.
Lead results over time
Against the period ending 2021 (0 ppb) the latest result is about the same. The highest 90th-percentile result EPA holds for Desert Oasis is 2.1 ppb across 4 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2024 | 0 (not detected) |
| 2021 | 0 (not detected) |
| 2020 | 0 (not detected) |
| 2017 | 2.1 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. Desert Oasis's reported as 0 (not detected) sits at the 65th percentile in Arizona and the 39th nationally (higher means more lead). Systems reporting 0 tie at the bottom, so the rank mostly reflects size among them.
Other water systems in Maricopa County
99 other systems share Maricopa County; 24 of them have a higher latest lead result than Desert Oasis. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Phoenix City Of | 1,695,000 | 2.74 ppb |
| Mesa City Of | 466,000 | 5.01 ppb |
| Gilbert, Town Of | 247,600 | 0 (not detected) |
| Chandler City Of | 247,328 | 1.4 ppb |
| Scottsdale City Of | 241,361 | 2.3 ppb |
| Glendale City Of | 234,766 | 2.11 ppb |
| Peoria City Of | 187,676 | 0 (not detected) |
| Tempe City Of | 165,000 | 4.4 ppb |
| Epcor - Agua Fria | 128,040 | 0 (not detected) |
| Avondale City Of | 96,130 | 0 (not detected) |
Next steps for Surprise, AZ
Look up your address in Desert Oasis'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 Desert Oasis 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. Why sampled homes are the worst-case ones is in the guide to reading the number. A zero today does not rule out a jump later - the rules are tightening in 2027.