Summit Water Coop, AZ
Lead detected, under the action levels
Latest 90th-percentile lead: 7 ppb (monitoring period 2023-2025). The federal action level is 15 ppb today and drops to 10 ppb in Nov 2027; EPA's health goal is 0. Lead was measured in sampled homes but the 90th percentile is under both action levels. EPA's health goal for lead is zero, so test your own tap if your home was built before 1986 or anyone in it is pregnant or a young child.
Who runs the water here
Summit Water Coop serves about 53 people through 21 service connections, which makes it a very small system under EPA's size classes. It is under mixed public and private ownership and draws groundwater, in Pima County, Arizona. EPA system ID: AZ0420595; phone on file: 520-409-2057. They can tell you what your service line is made of and whether they pay to replace it.
Every lead result on file
That is down 3 ppb from 10 ppb in the period ending 2022. The highest 90th-percentile result EPA holds for Summit Water Coop is 10 ppb across 4 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2025 | 7 ppb |
| 2022 | 10 ppb |
| 2019 | 4.87 ppb |
| 2016 | 2 ppb |
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. Summit Water Coop's 7 ppb sits at the 94th percentile in Arizona and the 95th nationally (higher means more lead).
Neighbouring systems
137 other systems share Pima County; 5 of them have a higher latest lead result than Summit Water Coop. 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
Test your own tap with a certified lab first-draw sample; Tucson, 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 Summit Water Coop 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. Size matters more than most people expect: small vs large water systems.