Big Stone City, SD · PWSID SD4600007
Big Stone City lead service lines
112 lines still unidentified
Big Stone City reported no confirmed lead service lines, but 112 of 409 lines (27%) are still listed as "lead status unknown." Until a line is identified, treat it as possibly lead.
0% of Big Stone City's service lines are lead or galvanized requiring replacement. That's lower than the South Dakota average (0.8%) and lower than the national average (3.1%).
- Lead 0%
- Galvanized (replace) 0%
- Unknown 27%
- Non-lead 73%
Total service lines reported: 409. Reported all required service line types. Population served: 412; 283 connections.
Lead test results
Big Stone City's most recent 90th-percentile lead result (2023) was 1 ppb, below both the 15 ppb action level and the 10 ppb level that takes effect in 2027. This means 90% of homes sampled were at or below that level; individual homes, especially those with lead lines, can be higher.
Lead and Copper Rule 90th-percentile results reported to EPA, in parts per billion. Dashed lines: 15 ppb action level and the 10 ppb level from November 1, 2027.
Progress since 2025 Q1
Reported lead and galvanized-requiring-replacement lines went from 0 in 2025 Q1 to 0 in 2026 Q3: no change. Lines of unknown material went from 410 to 112, down 298 (73%).
Quarterly counts reported to EPA. A drop usually means lines were replaced or confirmed non-lead; a rise usually means more lines were identified. Replacement progress rankings.
Lead rule violations
EPA's data lists 1 Lead and Copper Rule violation since 2015 for Big Stone City. Health-based violations are treatment failures, such as corrosion control or public education; the rest are missed monitoring or reporting.
| Began | Violation | Status |
|---|---|---|
| Jul 2018 | Missed initial lead and copper tap sampling | Returned to compliance |
Source: EPA SDWIS violation records for the Lead and Copper Rule.
Where the water comes from
Big Stone City's main water source is purchased groundwater. It buys treated water from Grant-Roberts Rural Water System. The seller treats the water, including corrosion control that keeps lead from dissolving out of pipes, while Big Stone City is responsible for its own service line inventory and replacement program.
Source: EPA SDWIS water system and facility records.
Check your own address
These counts cover the whole system. To see whether your line is lead, use the utility's address-level inventory. Utilities had to prepare one by October 16, 2024 and make it publicly accessible; systems serving more than 50,000 people must post it online.
No map yet? Do the 2-minute scratch and magnet test on the pipe where water enters your home.
Protect your drinking water now
If your line is lead, galvanized or unknown, filter water for drinking, cooking and baby formula. Use a filter certified to NSF/ANSI 53 for lead. Run cold water for a few minutes after it sits for hours, and never use hot tap water for cooking.
How to pick a lead-certified filter · How to test your water for lead
Getting the line replaced
EPA's Lead and Copper Rule Improvements require most systems to replace lead and galvanized-requiring-replacement lines by December 31, 2037. Ask Big Stone City whether it replaces the private side for free or with a cost share before you hire anyone. If you want it done sooner, or your utility doesn't cover your side, a licensed plumber can quote it. What replacement costs.
County pages: Lead pipes in Grant County
Other water systems nearby
| System | Lead + galv. | Unknown |
|---|---|---|
| Grant-Roberts Rural Water System | 0 | 1 |
| Milbank | 11 | 1,404 |
Check another water system
Questions
Does Big Stone City have lead pipes?
It hasn't confirmed any, but 112 of its 409 service lines are still of unknown material, so lead has not been ruled out.
How do I check if my home's service line is lead?
Look up your address on Big Stone City's official service line inventory, which utilities must make publicly available. You can also scratch the pipe where it enters your home: lead is soft, dull gray, scratches to shiny silver and does not attract a magnet.
When will Big Stone City replace lead service lines?
Under EPA's Lead and Copper Rule Improvements, most systems must replace lead and galvanized-requiring-replacement lines by December 31, 2037, starting from November 1, 2027. The rule is being challenged in court, so dates could change. Many utilities run free or cost-share programs now.
Has Big Stone City had lead violations?
EPA's data shows 1 Lead and Copper Rule violation since 2015 for Big Stone City.
Which water filters remove lead?
Use a filter certified to NSF/ANSI Standard 53 for lead reduction, or NSF/ANSI 58 for reverse osmosis. Check the certification on NSF's listings, not just the box.
Embed or cite this data
Local news sites, blogs and community groups can embed this card. It updates when EPA releases new data.
Citation: Lead Pipe Map, "Big Stone City lead service lines," https://leadpipemap.com/sd/big-stone-city/. Source: EPA SDWIS service line inventory, 2026 Q3. Download the full dataset on the data page.