City Of Mountain View, CA
Lead reported as not detected
Latest 90th-percentile lead: reported as 0 (not detected) (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. 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
City Of Mountain View serves about 81,340 people through 17,968 service connections, which makes it a large system under EPA's size classes. It is owned by a local government (city, town, county or district) and draws surface water, in Santa Clara County, California. EPA system ID: CA4310007; phone on file: 650-903-6140. They can tell you what your service line is made of and whether they pay to replace it.
Lead results over time
Against the period ending 2022 (0 ppb) the latest result is about the same. The highest 90th-percentile result EPA holds for City Of Mountain View is 7.7 ppb across 4 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2025 | 0 (not detected) |
| 2022 | 0 (not detected) |
| 2019 | 0 (not detected) |
| 2016 | 7.7 ppb |
How City Of Mountain View 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. City Of Mountain View's reported as 0 (not detected) sits at the 61st percentile in California and the 40th nationally (higher means more lead). Systems reporting 0 tie at the bottom, so the rank mostly reflects size among them.
Other water systems in Santa Clara County
72 other systems share Santa Clara County; 28 of them have a higher latest lead result than City Of Mountain View. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| San Jose Water | 1,039,920 | 0 (not detected) |
| City Of Sunnyvale | 157,566 | 0 (not detected) |
| City Of Santa Clara | 134,587 | 2.7 ppb |
| Great Oaks Wc Inc | 112,582 | 0 (not detected) |
| City Of San Jose - Evg/Edv/Coy | 99,783 | 0 (not detected) |
| City Of Milpitas | 81,915 | 2.5 ppb |
| City Of Palo Alto | 67,658 | 0 (not detected) |
| Cwsc Los Altos Suburban | 63,559 | 1.5 ppb |
| City Of Gilroy | 59,426 | 2 ppb |
| City Of San Jose - Nsj/Alviso | 48,082 | 0 (not detected) |
What to do in your house
Look up your address in City Of Mountain View'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 City Of Mountain View 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. Small systems behave differently: why small systems go over more often.