Muir Beach Community, CA
Lead detected, under the action levels
Latest 90th-percentile lead: 10 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. Lead was measured in sampled homes but the 90th percentile is under both action levels. EPA's health goal for lead is zero, so test your own tap if your home was built before 1986 or anyone in it is pregnant or a young child.
Who runs the water here
Muir Beach Community serves about 336 people through 162 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 Marin County, California. EPA system ID: CA2100508; phone on file: 415-388-7804. Ask them for your address in their service line inventory - every system had to publish one by Oct 2024.
Every lead result on file
That is up 5.9 ppb from 4.1 ppb in the period ending 2020. The highest 90th-percentile result EPA holds for Muir Beach Community is 10 ppb across 3 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2023 | 10 ppb |
| 2020 | 4.1 ppb |
| 2017 | 9 ppb |
How Muir Beach Community 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. Muir Beach Community's 10 ppb sits at the 97th percentile in California and the 97th nationally (higher means more lead).
Other water systems in Marin County
13 other systems share Marin County; 0 of them have a higher latest lead result than Muir Beach Community. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Marin Municipal Water District | 188,116 | 0 (not detected) |
| North Marin Water District | 61,691 | 0 (not detected) |
| Bolinas Community Pud | 1,937 | 0 (not detected) |
| North Marin Wd - Pt. Reyes | 1,841 | 0 (not detected) |
| Inverness Public Utility Dist | 1,445 | 5.3 ppb |
| Lawson S Landing | 946 | 0 (not detected) |
| Stinson Beach County Wtr Dist | 583 | 0 (not detected) |
| Coast Springs - Cal. Water Service (Puc) | 445 | 0 (not detected) |
| Estero Mutual | 206 | 0 (not detected) |
| Green Gulch Farm | 75 | 3 ppb |
Next steps for Muir Beach, CA
Test your own tap with a certified lab first-draw sample; Muir Beach, 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 Muir Beach Community 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. Why sampled homes are the worst-case ones is in the guide to reading the number. The action level is dropping - the 10 ppb rule from 2027.