Jefferson, WI · PWSID WI1280104
Jefferson Waterworks lead service lines
335 lead or galvanized lines to replace
Jefferson Waterworks reported 304 lead and 31 galvanized-requiring-replacement service lines out of 2,994 in its inventory. That's 11% of all its lines. Another 0 (0%) are still listed as unknown material.
Ranks #44 of 258 Wisconsin systems with confirmed lead lines, and #883 nationally.
11% of Jefferson Waterworks's service lines are lead or galvanized requiring replacement. That's about the same as the Wisconsin average (11%) and higher than the national average (3.1%).
- Lead 10%
- Galvanized (replace) 1.0%
- Unknown 0%
- Non-lead 89%
Total service lines reported: 2,994. Reported all required service line types. Population served: 7,926; 3,072 connections.
Lead test results
Jefferson Waterworks's most recent 90th-percentile lead result (Jul 2024–Dec 2024) was 3.5 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 289 in 2025 Q1 to 335 in 2026 Q3: up 46 (16%). Lines of unknown material went from 202 to 0, down 202 (100%).
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 Jefferson Waterworks. Health-based violations are treatment failures, such as corrosion control or public education; the rest are missed monitoring or reporting.
| Began | Violation | Status |
|---|---|---|
| Oct 2024 | Lead consumer notice not delivered or reported | Returned to compliance |
Source: EPA SDWIS violation records for the Lead and Copper Rule.
Where the water comes from
Jefferson Waterworks's main water source is groundwater (wells).
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 Jefferson Waterworks 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 Jefferson County
Other water systems nearby
| System | Lead + galv. | Unknown |
|---|---|---|
| Watertown Waterworks | 934 | 1 |
| Fort Atkinson Waterworks | 788 | 46 |
| Lake Mills Waterworks | 152 | 5 |
| Johnson Creek Waterworks | 11 | 37 |
| Palmyra Waterworks | 63 | 449 |
| Tremain Mobile Home Park | 0 | 182 |
| Breezy Knoll Community | 0 | 50 |
| Ripview Court 1 | 0 | 18 |
Check another water system
Questions
Does Jefferson Waterworks have lead pipes?
Yes. Jefferson Waterworks reported 304 lead service lines and 31 galvanized lines that must be replaced, out of 2,994 total. 0 more are of unknown material.
How do I check if my home's service line is lead?
Look up your address on Jefferson Waterworks'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 Jefferson Waterworks 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 Jefferson Waterworks had lead violations?
EPA's data shows 1 Lead and Copper Rule violation since 2015 for Jefferson Waterworks.
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, "Jefferson Waterworks lead service lines," https://leadpipemap.com/wi/jefferson-waterworks/. Source: EPA SDWIS service line inventory, 2026 Q3. Download the full dataset on the data page.