San Mateo Mdwca, NM
Lead detected, under the action levels
Latest 90th-percentile lead: 1.7 ppb (monitoring period 2026-2026). 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.
About San Mateo Mdwca
San Mateo Mdwca serves about 182 people through 55 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 Cibola County, New Mexico. EPA system ID: NM3525733; phone on file: 505-287-8108. Call that number and ask whether your address has a lead, galvanized or unknown service line.
Lead results over time
Against the period ending 2024 (1.1 ppb) the latest result is about the same. The highest 90th-percentile result EPA holds for San Mateo Mdwca is 1.7 ppb across 6 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2026 | 1.7 ppb |
| 2024 | 1.1 ppb |
| 2022 | 1.1 ppb |
| 2019 | 1.4 ppb |
| 2018 | 1.4 ppb |
| 2016 | 0.32 ppb |
Against other New Mexico systems
Of the 504 New Mexico systems with a lead result, the median latest reading is 1.4 ppb; 14 are over 15 ppb right now and 46 have gone over at some point. San Mateo Mdwca's 1.7 ppb sits at the 54th percentile in New Mexico and the 66th nationally (higher means more lead).
Neighbouring systems
8 other systems share Cibola County; 6 of them have a higher latest lead result than San Mateo Mdwca. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Grants Domestic Water System | 10,523 | 4 ppb |
| Milan Community Water System | 2,560 | 3 ppb |
| San Rafael Water & Sanitation District | 1,060 | 2 ppb |
| Bluewater Water And Sanitation District | 492 | 1.3 ppb |
| Bluewater Acres Wua | 331 | 2 ppb |
| Bibo Mutual Domestic Water Assoc | 241 | 0 (not detected) |
| Seboyeta Water System | 209 | 2 ppb |
| Moquino Water System | 55 | 2 ppb |
What to do in your house
Test your own tap with a certified lab first-draw sample; Milan, NM 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 San Mateo Mdwca 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.