San Luis Wsd, CO
Lead reported as not detected
Latest 90th-percentile lead: reported as 0 (not detected) (monitoring period 2023-2025). 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.
Who runs the water here
San Luis Wsd serves about 629 people through 414 service connections, which makes it a small system under EPA's size classes. It is owned by a local government (city, town, county or district) and draws groundwater, in Costilla County, Colorado. EPA system ID: CO0112900; phone on file: 719-672-4100. Ask them for your address in their service line inventory - every system had to publish one by Oct 2024.
Lead results over time
Against the period ending 2021 (0 ppb) the latest result is about the same. The highest 90th-percentile result EPA holds for San Luis Wsd is 1 ppb across 7 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2025 | 0 (not detected) |
| 2021 | 0 (not detected) |
| 2020 | 0 (not detected) |
| 2019 | 1 ppb |
| 2018 | 0 (not detected) |
| 2017 | 0 (not detected) |
| 2016 | 0 (not detected) |
Against other Colorado systems
Of the 1,025 Colorado systems with a lead result, the median latest reading is 1 ppb; 2 are over 15 ppb right now and 71 have gone over at some point. San Luis Wsd's reported as 0 (not detected) sits at the 24th percentile in Colorado and the 24th nationally (higher means more lead). Systems reporting 0 tie at the bottom, so the rank mostly reflects size among them.
Neighbouring systems
7 other systems share Costilla County; 2 of them have a higher latest lead result than San Luis Wsd. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Costilla County Ws | 561 | 0 (not detected) |
| Ft Garland Wsd | 477 | 0 (not detected) |
| Blanca Town Of | 469 | 0 (not detected) |
| Garcia Domestic Wua | 100 | 0 (not detected) |
| Viejo San Acacio | 45 | 0 (not detected) |
| San Acacio Domestic Wa | 40 | 0.5 ppb |
| Lake Sanchez Estates | 34 | 1 ppb |
What to do in your house
Look up your address in San Luis Wsd'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 San Luis Wsd 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. Small systems behave differently: why small systems go over more often.