Rosario Park, CA
Lead reported as not detected
Latest 90th-percentile lead: reported as 0 (not detected) (monitoring period 2022-2024). 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.
Who runs the water here
Rosario Park serves about 38 people through 19 service connections, which makes it a very small system under EPA's size classes. It is privately owned and draws groundwater, in Santa Barbara County, California. EPA system ID: CA4200579; phone on file: 805-722-2017. Call that number and ask whether your address has a lead, galvanized or unknown service line.
Every lead result on file
Against the period ending 2021 (0 ppb) the latest result is about the same. The highest 90th-percentile result EPA holds for Rosario Park is 2.2 ppb across 3 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2024 | 0 (not detected) |
| 2021 | 0 (not detected) |
| 2018 | 2.2 ppb |
How Rosario Park compares
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. Rosario Park's reported as 0 (not detected) sits at the 4th percentile in California and the 2nd nationally (higher means more lead). Systems reporting 0 tie at the bottom, so the rank mostly reflects size among them.
Nearby utilities
62 other systems share Santa Barbara County; 15 of them have a higher latest lead result than Rosario Park. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| City Of Santa Maria Utilities Department | 112,208 | 0 (not detected) |
| City Of Santa Barbara Water Department | 93,334 | 2.5 ppb |
| Goleta Water District | 85,535 | 0 (not detected) |
| Lompoc-City Water Utility Div | 40,538 | 0 (not detected) |
| Golden State Water Company - Orcutt | 34,267 | 2.6 ppb |
| Carpinteria Valley Water District | 16,356 | 0 (not detected) |
| American Water O&M, Llc - Vsfb | 14,971 | 0 (not detected) |
| Montecito Water Dist | 12,010 | 0 (not detected) |
| Guadalupe Water Department | 8,897 | 0 (not detected) |
| Vandenberg Village Comm. Serv. Dist. | 7,308 | 0 (not detected) |
Your move
Look up your address in Rosario Park'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 Rosario Park 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. A zero today does not rule out a jump later - the rules are tightening in 2027.