Armstrong Valley-Cal Water Service (Puc), CA
Lead detected, under the action levels
Latest 90th-percentile lead: 3.2 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.
Armstrong Valley-Cal Water Service (Puc) at a glance
Armstrong Valley-Cal Water Service (Puc) serves about 539 people through 282 service connections, which makes it a small system under EPA's size classes. It is privately owned and draws groundwater, in Sonoma County, California. EPA system ID: CA4910018; phone on file: 408-367-8593. They can tell you what your service line is made of and whether they pay to replace it.
Armstrong Valley-Cal Water Service (Puc)'s lead record
Against the period ending 2022 (2.7 ppb) the latest result is about the same. The highest 90th-percentile result EPA holds for Armstrong Valley-Cal Water Service (Puc) is 4 ppb across 5 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2025 | 3.2 ppb |
| 2022 | 2.7 ppb |
| 2022 | 0 (not detected) |
| 2021 | 4 ppb |
| 2018 | 0 (not detected) |
Against other California systems
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. Armstrong Valley-Cal Water Service (Puc)'s 3.2 ppb sits at the 87th percentile in California and the 84th nationally (higher means more lead).
Nearby utilities
128 other systems share Sonoma County; 14 of them have a higher latest lead result than Armstrong Valley-Cal Water Service (Puc). If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Santa Rosa, City Of | 178,452 | 1.32 ppb |
| Petaluma, City Of | 61,427 | 0 (not detected) |
| Rohnert Park, City Of | 43,821 | 0 (not detected) |
| Windsor, Town Of | 25,561 | 0 (not detected) |
| Valley Of The Moon Water District | 23,140 | 0 (not detected) |
| Healdsburg, City Of | 10,972 | 0 (not detected) |
| Sonoma, City Of | 10,619 | 0 (not detected) |
| Cloverdale, City Of | 8,710 | 0 (not detected) |
| California-American Larkfield (Puc) | 7,911 | 6 ppb |
| Sebastopol, City Of | 7,522 | 0 (not detected) |
What to do in your house
Test your own tap with a certified lab first-draw sample; San Jose, CA 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 Armstrong Valley-Cal Water Service (Puc) whether it covers that cost before hiring anyone - many utilities now do. Its latest copper 90th percentile is 1355 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. Why sampled homes are the worst-case ones is in the guide to reading the number. The action level is dropping - the 10 ppb rule from 2027.