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1,900 Wisconsin water systems have inventoried 1,433,626 service lines for EPA. 146,244 (10%) are confirmed lead and 182,821 (13%) are still of unknown material. Below: every large or city-linked Wisconsin utility ranked by lead lines.
Wisconsin water systems reported 146,244 lead service lines and 12,594 galvanized lines requiring replacement as of Q2 2026 — 10% of the 1,433,626 lines inventoried and 6.7% of the national lead total, ranking #6 of 51. MILWAUKEE WATERWORKS reports the most in the state (65,331).
MILWAUKEE WATERWORKS (65,331), RACINE WATERWORKS (10,257), WEST ALLIS WATERWORKS (7,719) lead the list; 140 Wisconsin systems report at least one lead line in total.
Find your utility in the table below, then check its published service line inventory (most utilities post an address-lookup map) or call the number on your water bill. Utilities must notify customers whose line is lead, galvanized-requiring-replacement or unknown. You can also test the pipe entering your home: lead is soft, dull gray, non-magnetic and turns shiny when scratched.
Under EPA's Lead and Copper Rule Improvements, systems must replace lead and galvanized-requiring-replacement lines within 10 years starting in 2027; systems with very high counts can receive longer deadlines. Ask your utility for its replacement plan and whether it covers the homeowner-owned portion.
Use a filter certified to NSF/ANSI 53 for lead for drinking and cooking, flush the tap after water has sat for hours, never use hot tap water for drinking or infant formula, and confirm your actual level with a certified lab test.
Source: EPA SDWIS Service Line Inventory, Q2 2026 snapshot (updated 2026-08-18). Counts are service lines, not people.
1,894 of the 1,900 Wisconsin systems in EPA's Q2 2026 report have filed line counts. The 146,244 confirmed lead lines and 12,594 galvanized lines requiring replacement come from 140 systems — 7.4% of those reporting — so lead pipe in Wisconsin is concentrated in a small share of systems. 182,821 lines (13%) are still of unknown material, below the national share of 22%.
Why unknown lines matter: Under EPA's Lead and Copper Rule Revisions (LCRR), every community water system had to submit an initial service line inventory by October 16, 2024, and lines whose material could not be documented were reported as unknown. The Lead and Copper Rule Improvements (LCRI), finalized in October 2024, require systems to keep identifying those lines, to notify customers served by a lead, galvanized-requiring-replacement or unknown line, and to replace lead and galvanized-requiring-replacement lines — generally within 10 years of the rule's November 1, 2027 compliance date. The LCRI also lowers the lead action level from 15 to 10 ppb. For Wisconsin, that makes the 182,821 unknown lines (13%) the pool from which future confirmed-lead counts will be drawn.
Among the 1 Wisconsin utilities linked to a city report on this site, 1 reports at least one lead or galvanized-requiring-replacement line. The largest — MILWAUKEE WATERWORKS (626,000 served) — reports 65,331 lead respectively.
Your own answer is one lookup away: search your utility's service line inventory (usually an address map on its website), or read the water system name and lead results in your latest Consumer Confidence Report. Customers on a lead, galvanized-requiring-replacement or unknown line must be notified by the utility. Failing that, scratch the pipe at the water meter — lead is soft, dull gray, non-magnetic and turns shiny where scratched.
EPA's rule text and timelines are on its Lead and Copper Rule Improvements page. While your line is unverified, our best water filters for lead guide covers NSF/ANSI 53-certified options, and the lead in drinking water guide explains testing and health thresholds.
EPA SDWIS Service Line Inventory, Q2 2026 snapshot (updated 2026-08-18); regulatory dates from EPA's LCRR/LCRI pages.
Community systems serving 50,000+ people plus systems linked to a city report on this site (12 shown). State totals above include every reporting system.
| # | Water system | Status | Lead | GRR | Unknown | Total lines | City report |
|---|---|---|---|---|---|---|---|
| 1 | MILWAUKEE WATERWORKS WI2410100 · 626,000 served | Lead service lines present | 65,331 | 0 | 26,341 | 160,819 | Milwaukee → |
| 2 | RACINE WATERWORKS WI2520062 · 105,100 served | Lead service lines present | 10,257 | 394 | 1 | 33,837 | |
| 3 | WEST ALLIS WATERWORKS WI2410595 · 63,240 served | Lead service lines present | 7,719 | 0 | 758 | 19,440 | |
| 4 | OSHKOSH WATERWORKS WI4710457 · 63,000 served | Lead service lines present | 6,471 | 247 | 5,067 | 22,505 | |
| 5 | KENOSHA WATER UTILITY WI2300046 · 99,218 served | Lead service lines present | 1,677 | 124 | 7,369 | 29,446 | |
| 6 | EAU CLAIRE WATERWORKS WI6180230 · 70,587 served | Lead service lines present | 100 | 1 | 6,337 | 24,008 | |
| 7 | APPLETON WATERWORKS WI4450333 · 74,511 served | Lead service lines present | 4 | 727 | 377 | 28,818 | |
| 8 | GREEN BAY WATERWORKS WI4050356 · 107,369 served | Lead service lines present | 4 | 68 | 0 | 34,412 | |
| 9 | JANESVILLE WATER UTILITY WI1540127 · 64,415 served | Lead service lines present | 3 | 0 | 0 | 23,777 | |
| 10 | MADISON WATER UTILITY WI1130224 · 272,000 served | Lead service lines present | 2 | 0 | 0 | 65,536 | |
| 11 | WAUKESHA WATER UTILITY WI2680238 · 70,718 served | No lead service lines reported | 0 | 0 | 0 | 20,519 | |
| 12 | LA CROSSE WATERWORKS WI6320309 · 53,000 served | No lead service lines reported | 0 | 0 | 0 | 16,828 |
A lead or unknown service line means lead can enter water after it leaves the treatment plant, so city-level test results understate what reaches your tap. Filter drinking and cooking water with an NSF/ANSI 53 lead-certified system, and see the lead in drinking water guide or Wisconsin city water reports.
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