Green Gulch Farm, CA
Lead detected, under the action levels
Latest 90th-percentile lead: 3 ppb (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. 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
Green Gulch Farm serves about 75 people through 17 service connections, which makes it a very small system under EPA's size classes. It is privately owned and draws surface water, in Marin County, California. EPA system ID: CA2100565; phone on file: 415-942-2542. 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 3 ppb from 0 ppb in the period ending 2023. The highest 90th-percentile result EPA holds for Green Gulch Farm is 3 ppb across 4 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2026 | 3 ppb |
| 2023 | 0 (not detected) |
| 2020 | 0 (not detected) |
| 2017 | 0 (not detected) |
How Green Gulch Farm 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. Green Gulch Farm's 3 ppb sits at the 85th percentile in California and the 81st nationally (higher means more lead).
Neighbouring systems
13 other systems share Marin County; 3 of them have a higher latest lead result than Green Gulch Farm. 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) |
| Muir Beach Community | 336 | 10 ppb |
| Estero Mutual | 206 | 0 (not detected) |
What to do in your house
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 Green Gulch Farm 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. The lead result guide covers how utilities pick the homes they sample. The action level is dropping - the 10 ppb rule from 2027.