Boulder Colony, SD
Lead reported as not detected
Latest 90th-percentile lead: reported as 0 (not detected) (monitoring period 2025-2025). 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 Boulder Colony
Boulder Colony serves about 26 people through 8 service connections, which makes it a very small system under EPA's size classes. It is privately owned and draws groundwater, in Edmunds County, South Dakota. EPA system ID: SD4600339; phone on file: 6053801487. Ask them for your address in their service line inventory - every system had to publish one by Oct 2024.
Boulder Colony's lead record
Against the period ending 2025 (1 ppb) the latest result is about the same. The highest 90th-percentile result EPA holds for Boulder Colony is 1 ppb across 2 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2025 | 0 (not detected) |
| 2025 | 1 ppb |
How Boulder Colony compares
Of the 458 South Dakota systems with a lead result, the median latest reading is 2 ppb; 0 are over 15 ppb right now and 6 have gone over at some point. Boulder Colony's reported as 0 (not detected) sits at the 0th percentile in South Dakota 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
5 other systems share Edmunds County; 5 of them have a higher latest lead result than Boulder Colony. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Ipswich | 928 | 1 ppb |
| Mina Lake Sanitary District | 863 | 2 ppb |
| Bowdle | 470 | 2 ppb |
| Roscoe | 269 | 2 ppb |
| Hosmer | 170 | 3 ppb |
Your move
Look up your address in Boulder Colony'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 Boulder Colony 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. Small systems behave differently: why small systems go over more often.