Big Basin Water Company, CA
Above the new 10 ppb level coming in 2027
Latest 90th-percentile lead: 12 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.
About Big Basin Water Company
Big Basin Water Company serves about 1,120 people through 540 service connections, which makes it a small system under EPA's size classes. It is privately owned and draws groundwater, in Santa Cruz County, California. EPA system ID: CA4410001; phone on file: 949-281-6542. Call that number and ask whether your address has a lead, galvanized or unknown service line.
Big Basin Water Company's lead record
That is up 10.9 ppb from 1.1 ppb in the period ending 2023. The highest 90th-percentile result EPA holds for Big Basin Water Company is 12 ppb across 5 monitoring periods, none of them over 15 ppb (1 over 10 ppb).
| Period ending | 90th-percentile lead |
|---|---|
| 2025 | 12 ppb over 10 |
| 2023 | 1.1 ppb |
| 2023 | 1.1 ppb |
| 2017 | 2.12 ppb |
| 2017 | 2.12 ppb |
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. Big Basin Water Company's 12 ppb sits at the 98th percentile in California and the 98th nationally (higher means more lead).
Nearby utilities
51 other systems share Santa Cruz County; 0 of them have a higher latest lead result than Big Basin Water Company. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Santa Cruz Water Department | 94,626 | 0 (not detected) |
| Watsonville, City Of | 65,231 | 1.2 ppb |
| Soquel Creek Water District | 40,962 | 2 ppb |
| San Lorenzo Valley Water Dist | 21,513 | 2.7 ppb |
| Scotts Valley Water District | 11,197 | 0.69 ppb |
| Slvwd - Felton Water System | 4,491 | 0.95 ppb |
| Central Water District | 2,726 | 0 (not detected) |
| Mission Springs Conference Center | 1,310 | 2.4 ppb |
| Mt. Hermon Association, Inc. | 1,176 | 0 (not detected) |
| Forest Lakes Mwc | 1,067 | 3.3 ppb |
What to do in your house
Test your own tap with a certified lab first-draw sample; Irvine, 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 Big Basin 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. What a 90th-percentile result does and does not tell you: how to read a lead result. This system is in the band the 2027 10 ppb rule changes.