Selby, SD
Lead detected, under the action levels
Latest 90th-percentile lead: 1 ppb (monitoring period 2024-2024). 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
Selby serves about 645 people through 367 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 surface water, in Walworth County, South Dakota. EPA system ID: SD4600291; phone on file: 6056497874. Call that number and ask whether your address has a lead, galvanized or unknown service line.
Lead results over time
Against the period ending 2022 (0 ppb) the latest result is about the same. The highest 90th-percentile result EPA holds for Selby is 1 ppb across 3 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2024 | 1 ppb |
| 2022 | 0 (not detected) |
| 2018 | 1 ppb |
Against other South Dakota systems
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. Selby's 1 ppb sits at the 39th percentile in South Dakota and the 53rd nationally (higher means more lead).
Nearby utilities
2 other systems share Walworth County; 1 of them has a higher latest lead result than Selby. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Mobridge | 3,261 | 1 ppb |
| Java | 121 | 3 ppb |
Next steps for Selby, SD
Test your own tap with a certified lab first-draw sample; Selby, SD 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 Selby 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.