Ellsworth Afb, SD
Lead detected, under the action levels
Latest 90th-percentile lead: 1 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.
Who runs the water here
Ellsworth Afb serves about 9,100 people through 2,000 service connections, which makes it a medium-sized system under EPA's size classes. It is federally owned and draws surface water, in Pennington County, South Dakota. EPA system ID: SD4680004; phone on file: 6053855395. Ask them for your address in their service line inventory - every system had to publish one by Oct 2024.
Every lead result on file
Against the period ending 2022 (1 ppb) the latest result is about the same. The highest 90th-percentile result EPA holds for Ellsworth Afb is 3 ppb across 4 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2025 | 1 ppb |
| 2022 | 1 ppb |
| 2019 | 3 ppb |
| 2016 | 2 ppb |
Where this result ranks
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. Ellsworth Afb's 1 ppb sits at the 48th percentile in South Dakota and the 55th nationally (higher means more lead).
Neighbouring systems
64 other systems share Pennington County; 35 of them have a higher latest lead result than Ellsworth Afb. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Rapid City | 72,009 | 6 ppb |
| Box Elder | 14,000 | 2 ppb |
| Rapid Valley Sanitary District | 11,408 | 3 ppb |
| Colonial Pine Hills Sanitary Distric | 1,200 | 1 ppb |
| Chapel Lane Water Company | 1,200 | 2 ppb |
| Hill City | 872 | 1 ppb |
| Wall | 699 | 1 ppb |
| New Underwood | 679 | 1 ppb |
| Hisega Meadows Water Inc | 493 | 1 ppb |
| Hart Ranch | 468 | 1 ppb |
Your move
Test your own tap with a certified lab first-draw sample; Ellsworth Afb, 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 Ellsworth Afb 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. The action level is dropping - the 10 ppb rule from 2027.