Rillito Water Users Assoc, AZ
Above the new 10 ppb level coming in 2027
Latest 90th-percentile lead: 12 ppb (monitoring period 2021-2023). The federal action level is 15 ppb today and drops to 10 ppb in Nov 2027; EPA's health goal is 0. Under the current 15 ppb rule this is not an exceedance, but it is above the 10 ppb action level that takes over in Nov 2027. Test your own tap; filter if your result shows lead.
Who runs the water here
Rillito Water Users Assoc serves about 165 people through 55 service connections, which makes it a very small system under EPA's size classes. It is privately owned and draws groundwater, in Pima County, Arizona. EPA system ID: AZ0410098; phone on file: 520-609-2245. Call that number and ask whether your address has a lead, galvanized or unknown service line.
Lead results over time
That is up 12 ppb from 0 ppb in the period ending 2020. The highest 90th-percentile result EPA holds for Rillito Water Users Assoc is 12 ppb across 3 monitoring periods, none of them over 15 ppb (1 over 10 ppb).
| Period ending | 90th-percentile lead |
|---|---|
| 2023 | 12 ppb over 10 |
| 2020 | 0 (not detected) |
| 2017 | 0 (not detected) |
Where this result ranks
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. Rillito Water Users Assoc's 12 ppb sits at the 98th percentile in Arizona and the 98th nationally (higher means more lead).
Neighbouring systems
137 other systems share Pima County; 1 of them has a higher latest lead result than Rillito Water Users Assoc. 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 Rillito, AZ
Test your own tap with a certified lab first-draw sample; Rillito, AZ may offer free or low-cost kits through the utility. If your own line is lead, replacing the private side runs about $1,200-$12,300 (EPA average about $4,700). Ask Rillito Water Users Assoc 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. What a 90th-percentile result does and does not tell you: how to read a lead result. See what changes at 10 ppb in 2027.