Granite Mountain Water Company, AZ
Above the new 10 ppb level coming in 2027
Latest 90th-percentile lead: 11 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. 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.
Granite Mountain Water Company at a glance
Granite Mountain Water Company serves about 381 people through 155 service connections, which makes it a very small system under EPA's size classes. It is privately owned and draws groundwater, in Yavapai County, Arizona. EPA system ID: AZ0413150; phone on file: 928-778-2600. Call that number and ask whether your address has a lead, galvanized or unknown service line.
Every lead result on file
That is up 11 ppb from 0 ppb in the period ending 2022. The highest 90th-percentile result EPA holds for Granite Mountain Water Company is 11 ppb across 4 monitoring periods, none of them over 15 ppb (1 over 10 ppb).
| Period ending | 90th-percentile lead |
|---|---|
| 2025 | 11 ppb over 10 |
| 2022 | 0 (not detected) |
| 2019 | 2.9 ppb |
| 2016 | 1 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. Granite Mountain Water Company's 11 ppb sits at the 97th percentile in Arizona and the 98th nationally (higher means more lead).
Neighbouring systems
100 other systems share Yavapai County; 3 of them have a higher latest lead result than Granite Mountain Water Company. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Town Of Prescott Valley | 57,048 | 0 (not detected) |
| Prescott City Of | 42,217 | 0 (not detected) |
| Cottonwood Municipal Water Cw1 | 11,288 | 0 (not detected) |
| Big Park Water Company | 7,392 | 0 (not detected) |
| Town Of Camp Verde Utilities | 5,380 | 0 (not detected) |
| Clarkdale Municipal Water System | 5,201 | 0 (not detected) |
| Cottonwood Municipal Water Vv6 | 4,518 | 18 ppb |
| Cordes Lakes Water Company | 4,425 | 4.1 ppb |
| Arizona Water Co - Rimrock | 3,532 | 0 (not detected) |
| Freeport Mcmoran Bagdad Town | 3,200 | 0 (not detected) |
What to do in your house
Test your own tap with a certified lab first-draw sample; Chino Valley, 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 Granite Mountain Water Company 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. See what changes at 10 ppb in 2027.