Hermosa Water Users Association, SD
Lead detected, under the action levels
Latest 90th-percentile lead: 2 ppb (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. 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 Hermosa Water Users Association
Hermosa Water Users Association serves about 108 people through 49 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 Custer County, South Dakota. EPA system ID: SD4602180. Ask the utility on your bill for your address in their service line inventory.
Hermosa Water Users Association's lead record
Against the period ending 2022 (2 ppb) the latest result is about the same. The highest 90th-percentile result EPA holds for Hermosa Water Users Association is 4 ppb across 5 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2025 | 2 ppb |
| 2022 | 2 ppb |
| 2020 | 1 ppb |
| 2019 | 1 ppb |
| 2016 | 4 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. Hermosa Water Users Association's 2 ppb sits at the 58th percentile in South Dakota and the 70th nationally (higher means more lead).
Other water systems in Custer County
9 other systems share Custer County; 3 of them have a higher latest lead result than Hermosa Water Users Association. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Custer | 1,919 | 2 ppb |
| Hermosa-Old System | 420 | 7 ppb |
| Spring Creek Acres | 172 | 1 ppb |
| Buffalo Gap | 126 | 2 ppb |
| Heartland Country Ranchettes | 95 | 1 ppb |
| Rock Ridge Court | 74 | 3 ppb |
| Fairburn Water Association | 65 | 3 ppb |
| North Hermosa Wud | 40 | 1 ppb |
| Paramount Point | 40 | 1 ppb |
What to do in your house
Test your own tap with a certified lab first-draw sample; Hermosa, 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 Hermosa Water Users Association 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. Size matters more than most people expect: small vs large water systems.