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

Tom Neltner, JD, is the director of chemicals policy

Note to Readers: As we are all grappling with the serious global health challenge of COVID-19, we would like to acknowledge the essential service that water utility health professionals provide to making clean water not just for drinking but also for washing our hands and our environment to be delivered. In the meantime, we continue to work on improving health and environmental protection – including reducing lead in drinking water. We will continue to share developments regarding lead in drinking water that you may find useful. In the meantime, please stay safe and sound.

With the comment deadline now closed for the Environmental Protection Agency’s proposed changes to its Lead and Copper Rule (LCR), the agency’s staff are currently reviewing the 687 different comments submitted to the Docket with the aim of doing this to finish the rule by the end of the year. The cover article in the March issue of the journal AWWA walks readers through the proposal and its implications to help water professionals plan ahead. It ends with six proposals for water systems that include developing a material inventory for service lines and identifying funding strategies to expedite full lead service line (LSL) replacement.

With this in mind, we continue our work to assess government efforts to develop LSL stocks by looking at reporting from municipal and private water utilities in Wisconsin[1] to the State Commission for Public Service (PSC) for the calendar year 2018.[2] Of the other states with mandatory inventory reporting, we have already covered Illinois in detail and will evaluate Michigan’s newly published reports shortly. The only other reporting state is California, but it has limited value as it only covers the portion of the service line owned by the utility and excludes the portion of private ownership.

Wisconsin’s coverage is similar to that of Illinois, but it is more detailed

As in Illinois, Wisconsin requires annual reporting and publishes the information online in a publicly available format as soon as it is received. However, Wisconsin differs in that utility companies require:

  1. Report the utility and the private side of the service line separately. For the vast majority of utility companies in Wisconsin, the utility side is the portion from the main street to the curb, and the private side is from the curb to the meter in the building. Reporting on the utility side began in 2004 and on the private side in 2017. There is no clear way of linking the count for each type of service line for the reports on the utility and private side.
  2. Include the number of each type of service line material categorized according to the diameter of the pipe. We are not aware of any other state that collects this information.
  3. Assign all lines to a specific material. In 2018 and in previous reporting years, there was no option to report service line material as “Unknown”. If a supplier was unsure about a material type, they likely reported the material type as “Other Metal”. For the 2019 reporting year, the PSC replaced the “Other Metal” categories with “Unknown – May contain lead” and “Unknown – Does not contain lead” and provided information on the new categories in its annual report help document for local and local authorities for small private utilities (see pages 15 and 17). Illinois first used these two categorization options in 2018.
  4. Take into account changes in the number of service lines categorized by material type at the beginning and end of the calendar year. This allows users to determine how many LSLs have been removed or decommissioned. It is also possible to keep track of how many lines of unknown material are assigned to lead, copper, plastic or some other material.

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

We have focused our analysis on private reporting. In 2018, Wisconsin utilities reported information on 1,098,138 private service lines. Of these, utilities indicated 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 company, reported 77,000 LSLs – half of the total water company – but reported no unknowns (aka “Other Metal”). In contrast, Madison, the second largest utility in the state and the first in the nation, replaced both customer and utility LSLs reporting 6 LSLs and 101 service lines as “Other Metal”. Table 1 provides details on the state’s ten largest utility companies.

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

Utility name total To lead Galvanized Other metal (unknown)
Milwaukee Water Works 165.382 76,868 0 0
Madison Water Utility 65.127 6th 4th 101
Appleton water department 27,416 207 0 23.103
Eau Claire Municipal Water Utility 26,347 1,416 0 24,931
Oshkosh City Water Company 20,584 6.557 0 14,027
Waukesha City Water Company 20,143 0 0 18,472
Kenosha Water Utility 20.104 2.403 2.281 0
West Allis Municipal Water Utility 19,677 7.429 0 142
Sheboygan Water Utility 19.296 4,772 694 5.315
Green Bay water company 18,569 52 1.603 0
For ten largest utilities in total 402.645 99.710 4,582 86.091
Overall for state 1,098,138 153,662 24,358 299.010
1) Copper, iron and steel are reported separately from other metals. For the sake of simplicity, they are not included in the table. “Other Metal” is considered unknown.
2) The government sums do not include data for the utility companies Superior Water, Light and Power.

Of the state’s 577 utilities, 467 reported not having lead and 100 reported not having lead, galvanized, or “other metal”.

It is important to note that in 2018, the total number of reported private lines is less than the total number of reported lines owned by utility companies. Since utilities in Wisconsin began reporting private utility information relatively recently, PSC employees anticipate that the quality of private utility coverage will improve over time, and the total number of private utility lines reported will improve over time will increase over time to better match the number of utility-owned lines, which totaled 1,375,739 in 2018.

Most LSLs are less than 1 inch in diameter

Conventional evidence has suggested that LSLs are rarely more than 2 inches in diameter, based on the Lead Industries Association’s 1950 book, Lead in Modern Plumbing. With that in mind, we were surprised to find that nine utility companies reported 532 lead pipes 2.5 to 10 inches in diameter. For example, a 2-inch lead pipe for water would have 3-inch-thick walls and weigh more than 9 pounds per foot. A utility company reported 182 ten-inch lead pipes but informed us that it was because they knew the pipes were lead but did not know the diameter. We anticipate that the number of larger diameter lead pipes will drop to near zero when utilities inspect these lines.

When we analyzed Wisconsin’s pipe diameter data by private service line material, we found that 82% of service lines were evenly split between 3/4 “and 1” in diameter, with 17% and 11% of those lines being made of lead, respectively. Forty-three percent of the 5/8 inch diameter service lines were lead. Above a diameter of 1 inch, the lead pipe was unusual at only 2%. The following table and illustration provide the details.

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

Wisconsin enables year-to-year progress to be tracked

With Wisconsin utilities having to report home numbers and categorize changes at the beginning and end of the year, the 2018 reports provide a way to track utility progress in replacing LSLs. For example:

  • 74 utility companies said they had taken 5,625 LSLs out of service.
  • 33 utilities reported a total net addition of 12,037 LSLs, most likely because they discovered that lines previously labeled “other metal” were lead.


Wisconsin has led the development of supportive guidelines to assist communities with replacement programs. In 2017, Wisconsin invested nearly $ 27 million in unsuccessful loans to 35 disadvantaged communities to completely replace LSLs. 29 municipalities received similar loans in 2018. That same year, lawmakers passed law allowing utility companies to provide financial assistance to customers to replace LSLs on private property. The inventory reporting shows that there has been progress in identifying and replacing LSLs. However, in Milwaukee in particular, much more is needed to significantly reduce these numbers.

In the meantime, we believe the pipe diameter breakdown observed in Wisconsin may be useful for utility companies looking to develop or refine their service line material inventories.

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

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

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