Castle Airport, CA
Exceeded the action level in the past
Latest 90th-percentile lead: 6.9 ppb (monitoring period 2021-2023). The federal action level is 15 ppb today and drops to 10 ppb in Nov 2027; EPA's health goal is 0. The latest result is under the action level, but this system has gone over 15 ppb before. Lead comes from pipes, not the source water, so a home with a lead service line can still be exposed. Test your own tap.
Who runs the water here
Castle Airport serves about 150 people through 134 service connections, which makes it a very small system under EPA's size classes. It is owned by a local government (city, town, county or district) and draws groundwater, in Merced County, California. EPA system ID: CA2410700; phone on file: 209-385-7686. They can tell you what your service line is made of and whether they pay to replace it.
Lead results over time
That is down 52.7 ppb from 59.6 ppb in the period ending 2020. The highest 90th-percentile result EPA holds for Castle Airport is 59.6 ppb across 3 monitoring periods, 1 of them over the 15 ppb action level.
| Period ending | 90th-percentile lead |
|---|---|
| 2023 | 6.9 ppb |
| 2020 | 59.6 ppb over 15 |
| 2017 | 9.03 ppb |
How Castle Airport 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. Castle Airport's 6.9 ppb sits at the 95th percentile in California and the 94th nationally (higher means more lead).
Neighbouring systems
21 other systems share Merced County; 0 of them have a higher latest lead result than Castle Airport. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| City Of Merced | 96,073 | 0 (not detected) |
| City Of Los Banos | 48,896 | 0 (not detected) |
| City Of Atwater | 29,479 | 0 (not detected) |
| City Of Livingston | 14,894 | 0 (not detected) |
| Winton Water & Sanitary Dist | 9,745 | 0 (not detected) |
| Delhi Cwd | 7,784 | 0 (not detected) |
| City Of Dos Palos | 7,452 | 0.56 ppb |
| City Of Gustine | 6,138 | 0 (not detected) |
| Cal Am - Meadowbrook | 5,723 | 6 ppb |
| Hilmar County Water District | 5,504 | 0 (not detected) |
What to do in your house
Test your own tap with a certified lab first-draw sample; Merced, 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 Castle Airport 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. Why an old exceedance still matters: over the limit before, under it now.