Grace Mar Wua, 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.
About Grace Mar Wua
Grace Mar Wua serves about 50 people through 13 service connections, which makes it a very small system under EPA's size classes. It is privately owned and draws groundwater, in Boulder County, Colorado. EPA system ID: CO0107321; phone on file: 720-201-6420. Ask them for your address in their service line inventory - every system had to publish one by Oct 2024.
Grace Mar Wua's lead record
That is down 1.5 ppb from 1.5 ppb in the period ending 2021. The highest 90th-percentile result EPA holds for Grace Mar Wua is 11.5 ppb across 7 monitoring periods, none of them over 15 ppb (1 over 10 ppb).
| Period ending | 90th-percentile lead |
|---|---|
| 2025 | 0 (not detected) |
| 2021 | 1.5 ppb |
| 2020 | 1.5 ppb |
| 2019 | 1 ppb |
| 2018 | 2.5 ppb |
| 2017 | 11.5 ppb over 10 |
| 2016 | 0.5 ppb |
How Grace Mar Wua compares
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. Grace Mar Wua's reported as 0 (not detected) sits at the 2nd percentile in Colorado and the 3rd nationally (higher means more lead). Systems reporting 0 tie at the bottom, so the rank mostly reflects size among them.
Nearby utilities
39 other systems share Boulder County; 17 of them have a higher latest lead result than Grace Mar Wua. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Boulder City Of | 166,080 | 2 ppb |
| Longmont City Of | 104,178 | 1.6 ppb |
| Erie Town Of | 47,444 | 2.6 ppb |
| Lafayette City Of | 28,700 | 2 ppb |
| Louisville City Of | 20,975 | 0 (not detected) |
| Left Hand Wd | 20,280 | 1 ppb |
| Superior Md No 1 | 17,900 | 0 (not detected) |
| Longs Peak Wd | 3,200 | 2 ppb |
| Lyons Town Of | 2,990 | 0 (not detected) |
| Nederland Town Of | 2,406 | 1 ppb |
What to do in your house
Look up your address in Grace Mar Wua'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 Grace Mar Wua 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.