Circle Oaks Water District, CA
Lead reported as not detected
Latest 90th-percentile lead: reported as 0 (not detected) (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. 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.
Circle Oaks Water District at a glance
Circle Oaks Water District serves about 500 people through 190 service connections, which makes it a very small system under EPA's size classes. It is privately owned and draws surface water, in Napa County, California. EPA system ID: CA2800521; phone on file: 707-966-1607. Ask them for your address in their service line inventory - every system had to publish one by Oct 2024.
Circle Oaks Water District's lead record
Against the period ending 2020 (0 ppb) the latest result is about the same. The highest 90th-percentile result EPA holds for Circle Oaks Water District is 14 ppb across 7 monitoring periods, none of them over 15 ppb (1 over 10 ppb).
| Period ending | 90th-percentile lead |
|---|---|
| 2023 | 0 (not detected) |
| 2020 | 0 (not detected) |
| 2019 | 5.6 ppb |
| 2018 | 2.7 ppb |
| 2017 | 0 (not detected) |
| 2017 | 6.3 ppb |
| 2016 | 14 ppb over 10 |
Where this result ranks
Of the 2,884 California systems with a lead result, the median latest reading is 0 ppb; 30 are over 15 ppb right now and 215 have gone over at some point. Circle Oaks Water District's reported as 0 (not detected) sits at the 37th percentile in California and the 22nd nationally (higher means more lead). Systems reporting 0 tie at the bottom, so the rank mostly reflects size among them.
Neighbouring systems
27 other systems share Napa County; 7 of them have a higher latest lead result than Circle Oaks Water District. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Napa, City Of | 84,804 | 0 (not detected) |
| American Canyon, City Of | 18,423 | 0 (not detected) |
| Calistoga, City Of | 5,610 | 0 (not detected) |
| St. Helena, City Of | 5,386 | 0 (not detected) |
| Town Of Yountville | 2,785 | 0 (not detected) |
| Howell Mountain Mutual Water Company | 1,244 | 0 (not detected) |
| Veterans Home Of California | 1,000 | 0 (not detected) |
| Pacific Union College | 758 | 7.8 ppb |
| Berryessa Highlands | 715 | 0 (not detected) |
| Adventist Health - St. Helena Hospital | 617 | 0 (not detected) |
Your move
Look up your address in Circle Oaks Water District'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 Circle Oaks Water District whether it covers that cost before hiring anyone - many utilities now do. Its latest copper 90th percentile is 1600 ppb (copper action level 1,300 ppb).
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. A zero today does not rule out a jump later - the rules are tightening in 2027.