Ilium Valley Ws, CO
Lead detected, under the action levels
Latest 90th-percentile lead: 1 ppb (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. 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
Ilium Valley Ws serves about 322 people through 74 service connections, which makes it a very small system under EPA's size classes. It is privately owned and draws groundwater, in San Miguel County, Colorado. EPA system ID: CO0157250; phone on file: 970-318-1803. Ask them for your address in their service line inventory - every system had to publish one by Oct 2024.
Lead results over time
That is down 5.3 ppb from 6.3 ppb in the period ending 2021. The highest 90th-percentile result EPA holds for Ilium Valley Ws is 10.5 ppb across 6 monitoring periods, none of them over 15 ppb (1 over 10 ppb).
| Period ending | 90th-percentile lead |
|---|---|
| 2025 | 1 ppb |
| 2021 | 6.3 ppb |
| 2020 | 1.8 ppb |
| 2019 | 2.1 ppb |
| 2018 | 0.7 ppb |
| 2017 | 10.5 ppb over 10 |
How Ilium Valley Ws 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. Ilium Valley Ws's 1 ppb sits at the 51st percentile in Colorado and the 53rd nationally (higher means more lead).
Neighbouring systems
11 other systems share San Miguel County; 4 of them have a higher latest lead result than Ilium Valley Ws. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Mountain Village Town Of | 9,700 | 1 ppb |
| Telluride Town Of | 7,900 | 1 ppb |
| Norwood Water Commission | 1,700 | 2 ppb |
| Aldasoro Ranch Hoc | 412 | 4.2 ppb |
| Wilson Mesa | 290 | 0 (not detected) |
| Ophir Town Of | 193 | 1.5 ppb |
| San Bernardo Hoa | 132 | 0.9 ppb |
| Elk Run Homeowners Corporation | 125 | 1 ppb |
| Last Dollar Pud | 96 | 11.9 ppb |
| Sawpit Town Of | 59 | 0 (not detected) |
Your move
Test your own tap with a certified lab first-draw sample; Ridgway, CO 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 Ilium Valley Ws 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. Size matters more than most people expect: small vs large water systems.