Rio Viejo Water, AZ
Lead reported as not detected
Latest 90th-percentile lead: reported as 0 (not detected) (monitoring period 2025-2027). 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
Rio Viejo Water serves about 272 people through 100 service connections, which makes it a very small system under EPA's size classes. It is owned by a local government (city, town, county or district) and draws groundwater, in Pima County, Arizona. EPA system ID: AZ0410011; phone on file: 520-326-4858. They can tell you what your service line is made of and whether they pay to replace it.
Every lead result on file
Against the period ending 2025 (0 ppb) the latest result is about the same. The highest 90th-percentile result EPA holds for Rio Viejo Water is 0 ppb across 5 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2027 | 0 (not detected) |
| 2025 | 0 (not detected) |
| 2023 | 0 (not detected) |
| 2020 | 0 (not detected) |
| 2020 | 0 (not detected) |
How Rio Viejo Water compares
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. Rio Viejo Water's reported as 0 (not detected) sits at the 26th percentile in Arizona and the 18th nationally (higher means more lead). Systems reporting 0 tie at the bottom, so the rank mostly reflects size among them.
Nearby utilities
137 other systems share Pima County; 44 of them have a higher latest lead result than Rio Viejo Water. 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 |
Your move
Look up your address in Rio Viejo Water'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 Rio Viejo Water 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. Small systems behave differently: why small systems go over more often.