Lopez Project, CA
Lead detected, under the action levels
Latest 90th-percentile lead: 0.79 ppb (monitoring period 2025-2025). 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
Lopez Project serves about 69 people through 31 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 surface water, in San Luis Obispo County, California. EPA system ID: CA4010022; phone on file: 805-473-7156. Ask them for your address in their service line inventory - every system had to publish one by Oct 2024.
Every lead result on file
Against the period ending 2025 (0.93 ppb) the latest result is about the same. The highest 90th-percentile result EPA holds for Lopez Project is 0.93 ppb across 2 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2025 | 0.79 ppb |
| 2025 | 0.93 ppb |
How Lopez Project 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. Lopez Project's 0.79 ppb sits at the 67th percentile in California and the 47th nationally (higher means more lead).
Other water systems in San Luis Obispo County
71 other systems share San Luis Obispo County; 22 of them have a higher latest lead result than Lopez Project. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| San Luis Obispo Water Department | 49,534 | 0 (not detected) |
| Atascadero Mutual Water Co | 33,307 | 0 (not detected) |
| City Of Paso Robles Water Division | 31,176 | 0 (not detected) |
| City Of Arroyo Grande Utilities Division | 17,963 | 0 (not detected) |
| California Mens Colony | 15,000 | 0 (not detected) |
| Nipomo Comm Services Dist | 13,771 | 0 (not detected) |
| City Of Grover Beach Public Works Dept | 12,701 | 0 (not detected) |
| Morro Bay Pw Dept - Water Division | 10,757 | 0 (not detected) |
| Templeton Csd | 8,041 | 0 (not detected) |
| Pismo Beach Water Department | 7,944 | 0 (not detected) |
What to do in your house
Test your own tap with a certified lab first-draw sample; San Luis Obispo, 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 Lopez Project 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. Systems that went over once often dip back under; here is what that means.