Mesa Water District, CA
Lead reported as not detected
Latest 90th-percentile lead: reported as 0 (not detected) (monitoring period 2024-2026). 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
Mesa Water District serves about 110,000 people through 24,975 service connections, which makes it a very large system under EPA's size classes. It is owned by a local government (city, town, county or district) and draws surface water, in Orange County, California. EPA system ID: CA3010004; phone on file: 949-207-5468. Ask them for your address in their service line inventory - every system had to publish one by Oct 2024.
Lead results over time
Against the period ending 2023 (0 ppb) the latest result is about the same. The highest 90th-percentile result EPA holds for Mesa Water District is 0 ppb across 5 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2026 | 0 (not detected) |
| 2023 | 0 (not detected) |
| 2020 | 0 (not detected) |
| 2020 | 0 (not detected) |
| 2017 | 0 (not detected) |
How Mesa Water District 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. Mesa Water District's reported as 0 (not detected) sits at the 62nd 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.
Nearby utilities
39 other systems share Orange County; 12 of them have a higher latest lead result than Mesa Water District. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Irvine Ranch Water District | 450,323 | 0 (not detected) |
| City Of Anaheim | 350,254 | 0 (not detected) |
| City Of Santa Ana | 316,184 | 0 (not detected) |
| City Of Huntington Beach | 201,000 | 0 (not detected) |
| City Of Garden Grove | 174,226 | 0 (not detected) |
| Moulton Niguel Water District | 168,315 | 0 (not detected) |
| Santa Margarita Water District | 165,275 | 0 (not detected) |
| City Of Fullerton | 140,054 | 1.5 ppb |
| City Of Orange | 120,770 | 2.33 ppb |
| Golden State Wc - West Orange County | 114,693 | 2.2 ppb |
Your move
Look up your address in Mesa 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 Mesa Water District 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.