Oku Incorporated, CA
Lead reported as not detected
Latest 90th-percentile lead: reported as 0 (not detected) (monitoring period 2020-2022). 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.
About Oku Incorporated
Oku Incorporated serves about 35 people through 10 service connections, which makes it a very small system under EPA's size classes. It is privately owned and draws groundwater, in San Mateo County, California. EPA system ID: CA4100540; phone on file: 650-245-3088. Call that number and ask whether your address has a lead, galvanized or unknown service line.
Every lead result on file
Against the period ending 2019 (0 ppb) the latest result is about the same. The highest 90th-percentile result EPA holds for Oku Incorporated is 5 ppb across 3 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2022 | 0 (not detected) |
| 2019 | 0 (not detected) |
| 2016 | 5 ppb |
Against other California systems
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. Oku Incorporated's reported as 0 (not detected) sits at the 3rd percentile in California and the 1st nationally (higher means more lead). Systems reporting 0 tie at the bottom, so the rank mostly reflects size among them.
Nearby utilities
35 other systems share San Mateo County; 17 of them have a higher latest lead result than Oku Incorporated. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| California Water Service - San Mateo | 103,536 | 4.4 ppb |
| City Of Daly City | 102,593 | 0 (not detected) |
| City Of Redwood City | 90,043 | 0 (not detected) |
| California Water Service-S San Francisco | 62,609 | 4.1 ppb |
| California Water Service - Bear Gulch | 60,382 | 4 ppb |
| City Of San Bruno | 42,631 | 0 (not detected) |
| North Coast County Water Dist | 38,546 | 0 (not detected) |
| Estero Municipal Improvement District | 36,556 | 0 (not detected) |
| California Water Service - San Carlos | 34,801 | 5.8 ppb |
| City Of Burlingame | 32,453 | 6.3 ppb |
What to do in your house
Look up your address in Oku Incorporated'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 Oku Incorporated 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. A zero today does not rule out a jump later - the rules are tightening in 2027.