Looking for Clues on Lead Service Line Inventories in the 7th DWINSA Update
While the initial Lead Service Line Inventory deadline has passed, we may not see the data being submitted to EPA right away. In the meantime, we’re examining the updated 7th DWINSA survey results to learn what we can about lead service line inventories across the country.
Earlier this year, the EPA released an update to the 7th DWINSA. This one-time chance offered water systems an opportunity to revise lead service line (LSL) inventories, a crucial determinant of how the Bipartisan Infrastructure Law’s (BIL) lead service line replacement (LSLR) funds are allocated to states, as with the 2025 preliminary allotments released last week. EPIC has already highlighted how these updates redistributed funds across the country.
While we wait for the submitted inventories (though that data won’t be linked to funding allotments), we’re investigating the survey responses to answer two high-level questions. First, what trends can we identify from these updated survey results? Second, how do these survey results compare to the original 7th DWINSA of April 2023 — how much information was gained?
National Trends
The updated LSL inventories contain 3,520 state systems, bringing the response rate up to 78%, from 67%. These systems categorized all of their service lines by whether they contain lead pipes, use lead connectors, contain galvanized pipe and whether it was downstream of lead sources, or whether the line materials are unknown.
2,740 (77%) systems reported 100% of the lines in their system, but 517 (18%) of these simply reported all of their line material as unknown
1,011 (28%) systems reported 100% of their service lines as known materials and found no lead risk
545 (15%) systems reported at least one lead service line
392 (11%) systems reported at least one line with lead connectors
336 (9%) systems reported at least one galvanized line previously downstream of lead
We can classify systems into three broad groups - those with known lead exposure, those without lead exposure, and those of unknown materials. The survey contains 45 million service lines. Surveyed systems reported just under 3.5 million lines (7%) as containing lead, 31 million (68%) are reportedly not including lead, and a remaining 11 million (24%) are of unknown materials.
While it’s encouraging that roughly 68% of reported service lines aren’t lead, that still leaves millions of lines to be replaced and tens of millions more either unknown or unreported.
State Trends
Considering individual states, the degree to which inventories are completed and include unknown materials and unreported lines varies dramatically.
This plot shows the portion of service lines for each state based on whether they are known materials and how many lines remain unreported. California leads the way with more than 90% of lines reported and of known materials. Eleven other states report more than 75% of lines of a known material, lead or otherwise. For twenty-three states, reported lines represent less than half of the total service lines.
With these distributions in mind, we can further investigate the reported known materials for each state.
For all but Illinois, non-lead lines tend to be the majority of those known and reported. But this sampled data doesn’t necessarily indicate the states with the highest lead concentrations, simply those that are already reported. In fact, this view is perhaps most helpful in identifying which states are ahead of the curve of identifying lead. For example, Illinois, Minnesota, Wisconsin, and Ohio appear to be leading the pack in terms of identifying lead.
In some states where there is little to no identified lead, such as several in the southeast region, the lack of identified lead could be due to not having as many lines to uncover, not prioritizing lead service line inventories before the recent emphasis, or a combination of both.
And while galvanized lines are not composed of lead, it is crucial to note they could have historically been downstream of lead and thus still present a risk. Not to mention there are numerous other reasons for replacing them while getting the lead out.
With roughly one-fourth of surveyed systems not responding to the survey, this view remains a keyhole glance into the presence of lead and the still incomplete view of service line materials across the country. Even so, it paints a picture of how these details may come into view as the Lead and Copper Rule Revisions (LCRR) inventory deadline approaches.
Information Gained
We next consider how these trends evolved from the original 7th DWINSA to this one-time update. To do so, we consider how the proportion of lines shifted across known, unknown, and not reported service lines changed between the two surveys.
Admittedly, this methodology abstracts the results of the survey a bit, but allows us a more straightforward comparison across states where the number of service lines vary dramatically due to size and population density.
States largely fall into one of four categories in terms of how the proportions shifted:
From Not Reported to Known Materials
From Not Reported to Unknown Materials
From Unknown to Known Materials
From Known Materials to Unknown or Not Reported
It’s worth noting that these results only let us examine broad trends of how survey results changed within a state in relation to one another. A percent change doesn’t necessarily mean a 1:1 exchange of, say, unknown materials for known materials in every case. Instead, it illustrates how the ratio of these categories shifted thanks to the updated survey results.
Let’s take a closer look at each.
From Not Reported to Known Materials
One of the most frequent results is that states reported an increased proportion of service line materials, with a mix of the results being known or unknown materials. In Alaska, a 30% decrease in Not Reported lines led to a 20% increase in known materials and 10% increase in unknown materials. Similar proportionate information gains played out in New York, Ohio, Wisconsin, Louisiana, and numerous other states.
The most dramatic shift took place in Maryland, where the original survey had contained almost entirely Not Reported service lines. The update saw a more than 50% increase in the known materials alongside an increase in the reported, but unknown material lines.
This trend highlights the reality many states find themselves in when it comes to replacing lead service lines — knowing is half the battle and while they haven’t reached that critical halfway point yet, they are making steady progress.
From Not Reported to Unknown Materials
In other states, we don’t see a dramatic increase in the percentage of known material lines, but observe states increasing the percentage of lines reported without identifying the materials.
In Illinois, an additional 10% of service lines are reported, but there is only a 1% increase in known material lines. The same trend can be seen in New Jersey, Pennsylvania, and Oregon.
While it is encouraging to see states reduce the number of Not Reported lines because it means they are communicating with the EPA, there is little concrete information gained when the reported unknowns outweigh the known lines. Additional clarity will be necessary for reaching the ambitious goal of replacing all lead service lines within a decade.
From Unknown to Known Materials
For a handful of states, the updated survey results saw a decrease in the percentage of lines reported as unknown materials and/or lines that were not reported and a proportionate increase in known materials.
In Kansas, for instance, there was a 40% shift in identifying the materials of previously unknown material service lines. It’s also worth highlighting this trend in Connecticut, Nebraska, and Tennessee.
These results are perhaps the most encouraging for measuring the success of the updated survey, as these states saw a tangible improvement in both the information gained and an increased clarity in identifying service line materials.
From Known Materials to Unknown or Not Reported
Most curiously, some states saw the percent change of known materials decrease as the percent not reported or unknown material lines increased proportionately.
In Utah, the percentage of known materials decreased by more than 20%, with three quarters of this change increasing the percent of unknown materials. Similar changes took place in Minnesota, Wyoming, and Indiana.
Likely due to an influx of newly reported, but unknown materials, this trend highlights that service line identification is not keeping pace with systems reported unknown materials, which has direct implications on EPA allocations.
All Eyes on the LSL Inventories
Exploring the updated 7th DWINSA survey results provides a valuable snapshot of progress in identifying lead service lines across the country. Even so, it is incomplete, with many of the survey results suggesting unreported and unknown materials in too many systems across the country.
On one hand, the survey is only a sample, whereas the upcoming mandated inventories should provide significantly more data and clarity. As states submit lead service line inventories, we’ll have a much more holistic view of progress across the country.
On the other hand, these results - their incomplete and ambiguous interpretation and all - may be a bellwether for the inventories to come.
If that’s the case, policymakers, system administrators, and advocates will need to work together all the more to drive innovation, reduce cost savings, and expand replacement efforts while working with imperfect data to remove lead nationwide within the decade.
EPIC believes we’re up to the challenge. To this end, we’ve provided a number of resources diving deeper into lead service line replacement:
How Far will BIL funding go to replace lead service lines? [Blog]
Advancing Lead Service Line Programs with Low or No-Cost Policies and Practices [Report]
Good Decision-Making and Planning for Lead Service Line Cost Efficiencies [Report]
EPIC will continue to analyze lead service line inventories as data becomes available. And, because DWINSA, not the mandated inventories, informs the historic BIL LSLR allotments to states, we’ll continue to monitor and weigh in on the 8th DWINSA as it unfolds.