Latest Wisconsin data on water service lines provides important insights, reveals over 150,000 lead pipes

Tom Neltner, J.D. is the Chemicals Policy Director

Note to readers: As we all grapple with the grave global health challenge from COVID-19, we want to acknowledge the essential service that the public health professionals at water utilities provide in delivering safe water not only for drinking but for washing our hands and our surroundings. In the meantime, we are continuing to work towards improved health and environmental protections – including reducing lead in drinking water. We’ll plan to keep sharing developments regarding lead in drinking water that may be useful to you. In the meantime, please stay safe and healthy.

With the comment period now closed on the Environmental Protection Agency’s proposed revisions to its Lead and Copper Rule (LCR), agency staff are busy reviewing the 687 distinct comments submitted to the docket with a goal of finalizing the rule by the end of the year. To help water professionals plan ahead, the cover article in the March edition of Journal AWWA walks readers through the proposal and its implications. It ends with six suggestions to water systems that include developing a service line material inventory and identifying funding strategies to accelerate full lead service line (LSL) replacement.

With this suggestion in mind, we are continuing our work evaluating state efforts to develop LSL inventories by taking a closer look at reporting by Wisconsin municipal and private water utilities[1] to the state Public Service Commission (PSC) for calendar year 2018.[2] Of the other states with mandatory inventory reporting, we have previously covered Illinois in detail and will evaluate Michigan’s newly released reports soon. The only other state with mandatory reporting is California, but it has limited value because it only covers the portion of the service line owned by the utility and excludes the portion on private property.

Wisconsin’s reporting is similar to Illinois’, but more detailed

Like Illinois, Wisconsin requires annual reporting and posts the information online in a publicly accessible format as it is received. However, Wisconsin differs by requiring utilities to:

  1. Separately report the utility and private sides of the service line. For the vast majority of Wisconsin utilities, the utility side is the portion from the main through the curb stop, and the private side is from the curb stop to the meter inside the building. Reporting on the utility side started in 2004 and on the private side in 2017. There is no clear way to connect the counts for each type of service line for the utility and private side reports.
  2. Report the number of each type of service line material categorized by the diameter of the line. We are not aware of any other state that collects this information.
  3. Assign all lines to a specific material. In 2018 and earlier reporting years, there was no option to report service line material as “Unknown.” If a utility was uncertain about a material type, it likely reported the material type as “Other Metal.” For the 2019 reporting year, the PSC replaced the “Other Metal” category with “Unknown – May Contain Lead” and “Unknown – Does Not Contain Lead” and provided information for utilities on the new categories in its Annual Report Help Document for municipal and small private utilities (see pages 15 and 17). Illinois first used these two categorization options in 2018.
  4. Account for changes in the number of service lines categorized by each material type at both the beginning and the end of the calendar year. This enables users to determine how many LSLs were removed or taken out of service. It also makes it possible to track how many lines of unknown material are reassigned to lead, copper, plastic or another material.

Wisconsin has 154,000 LSLs and more than twice as many unknowns

We focused our analysis on the private side reporting. In 2018, Wisconsin utilities reported information for 1,098,138 privately owned service lines. Of this total, utilities reported 153,662 (15%) as lead, 24,358 (2%) as galvanized steel, and 299,010 (27%) as “Other Metal.”

Milwaukee Water Works, the state’s largest water utility, reported 77,000 LSLs – half of the state’s total – but reported no unknowns (aka “Other Metal”) In contrast, Madison, the state’s second largest utility and the first in the nation to replace both customer- and utility-owned LSLs, reported 6 LSLs and 101 service lines as “Other Metal.” Table 1 provides details for the ten largest utilities in the state.

Number of service lines made of lead, galvanized, or other metal on private property reported by ten largest Wisconsin utilities at the end of 2018

Utility NameTotalLeadGalvanizedOther Metal (unknown)
Milwaukee Water Works165,38276,86800
Madison Water Utility65,12764101
Appleton Water Department27,416207023,103
Eau Claire Municipal Water Utility26,3471,416024,931
City of Oshkosh Water Utility20,5846,557014,027
City of Waukesha Water Utility20,1430018,472
Kenosha Water Utility20,1042,4032,2810
West Allis Municipal Water Utility19,6777,4290142
Sheboygan Water Utility19,2964,7726945,315
Green Bay Water Utility18,569521,6030
Total for ten largest utilities402,64599,7104,58286,091

Total for state 1,098,138153,66224,358299,010
1) Copper, iron, and steel reported separately from other metal. They are not included in the table for simplicity. “Other Metal” is considered unknown.
2) State totals do not include data for the utility Superior Water, Light, and Power.

Of the state’s 577 utilities, 467 reported having no lead, and 100 reported having no lead, galvanized, or “Other Metal.”

It is important to note that in 2018, the total number of private lines reported is less than the total number of utility owned lines reported. Because Wisconsin utilities started reporting private service line information fairly recently, PSC staff anticipates the quality of private service line reporting will improve over time and the total number of private service lines reported will increase over time to more closely match the number of utility-owned lines, which in 2018 totaled 1,375,739. 

Most LSLs less than 1” in diameter

Conventional wisdom tells us that LSLs were rarely made greater than 2” in diameter based on the 1950 “Lead in Modern Plumbing” book by the Lead Industries Association. With this in mind, we were surprised to see nine utilities reporting having 532 lead pipes ranging from 2.5” and 10” in diameter.  For context, a 2” lead pipe for water would have 3” thick walls and weigh more than 9 pounds per foot. One utility reported 182 ten-inch lead pipes, but told us that it was because they knew the pipes were lead but did not know the diameter. We anticipate that as the utilities investigate these lines, the number of larger diameter lead pipes will go down to nearly zero.

In evaluating Wisconsin’s pipe diameter data by material for private-side service lines, we found that 82% of service lines were evenly split between ¾” and 1” diameters with 17% and 11% of these lines respectively made of lead. Forty-three percent of 5/8” diameter service lines were lead. Above 1” diameter, lead pipe was uncommon at only 2%. The table and figure below provides the details.

When the PSC receives all of the reports for 2019 later this year, we will take a closer look, especially at the “Unknown – May Contain Lead” category.

Wisconsin enables tracking progress year-to-year

Because Wisconsin requires utilities to report private-side numbers at the beginning and end of the year and to categorize changes, the 2018 reports provide a means to track progress the utilities are making in LSL replacement.  For example:

  • 74 utilities reported retiring 5,625 LSLs from service.
  • 33 utilities reported a net total addition of 12,037 LSLs, most likely because they determined lines previously designated as “Other Metal” were found to be lead.


Wisconsin has led the way in developing supportive policies to assist communities with replacement programs. In 2017, Wisconsin invested almost $27 million in forgivable loans to 35 disadvantaged municipalities to fully replace LSLs. Twenty-nine municipalities received similar loans in 2018. That same year, the state legislature enacted a law allowing utilities to provide financial assistance to customers to replace LSLs on private property. From the inventory reporting, we are beginning to see progress in identifying and replacing LSLs but much more is needed, especially in Milwaukee, to substantially reduce those numbers.

In the meantime, we think the breakdown by pipe diameter seen in Wisconsin may be useful to those in utilities seeking to develop or refine their service line material inventories.

[1] The Public Service Commission regulates 574 municipal, one investor owned, and two small private utilities in Wisconsin. Superior Water Light and Power, Wisconsin’s one investor owned water utility, uses a different reporting program that does not currently require reporting of private service lines. PSC plans to add private service line information to the required reporting for this utility when it revises the reporting program in the near future.

[2] For consistency, we based analysis on reported numbers at the end of 2018.

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