North Sioux City, SD
Lead detected, under the action levels
Latest 90th-percentile lead: 4 ppb (monitoring period 2023-2023). 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 North Sioux City
North Sioux City serves about 3,042 people through 1,249 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 groundwater, in Union County, South Dakota. EPA system ID: SD4600226; phone on file: 6052329165. They can tell you what your service line is made of and whether they pay to replace it.
Every lead result on file
Against the period ending 2020 (4 ppb) the latest result is about the same. The highest 90th-percentile result EPA holds for North Sioux City is 4 ppb across 3 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2023 | 4 ppb |
| 2020 | 4 ppb |
| 2017 | 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. North Sioux City's 4 ppb sits at the 87th percentile in South Dakota and the 88th nationally (higher means more lead).
Other water systems in Union County
6 other systems share Union County; 0 of them have a higher latest lead result than North Sioux City. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Dakota Dunes Cid | 3,700 | 4 ppb |
| Beresford | 2,359 | 4 ppb |
| Elk Point | 2,124 | 2 ppb |
| Clay Rws/South Union | 1,447 | 1 ppb |
| Alcester | 820 | 1 ppb |
| Jefferson | 475 | 1 ppb |
Your move
Test your own tap with a certified lab first-draw sample; North Sioux City, 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 North Sioux City 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. Why sampled homes are the worst-case ones is in the guide to reading the number. The action level is dropping - the 10 ppb rule from 2027.