Replacing lead water service lines requires knowing where they are. Across much of the country that basic inventory did not exist, and building it turned out to be the hard part.
The pipe is split between two owners
A service line runs from the water main in the street to the building. In most systems the utility owns the portion up to a boundary and the property owner owns the rest.
Utilities keep records for their own side, sometimes reaching back a century. The private side is documented far less consistently, if at all.
That split also complicates replacement, because a utility cannot always work on private property without the owner's permission and, in many places, a funding arrangement.
Records are old, partial and inconsistent
Installation records may exist on paper cards, in hand-drawn maps or in permit files, produced under record-keeping practices that changed repeatedly over the decades.
Systems have merged, annexed neighboring areas and changed ownership, and records did not always survive those transitions intact.
Where records name a material, the entry describes what was recorded at installation rather than what is in the ground after later repairs and partial replacements.
Confirming a line usually means digging
Definitive identification often requires exposing the pipe, either at the meter, in the basement or through a small excavation in the yard or street.
Utilities use predictive methods to prioritize, combining housing age, neighborhood construction history and sampling, then verifying a subset physically.
Homeowners can check the visible portion where the line enters the building using simple scratch and magnet tests, though the visible section does not always match the buried run.
Why partial replacement is discouraged
Replacing only the utility-owned portion leaves lead in the ground and disturbs the remaining pipe, which can temporarily increase the amount of lead released into the water.
Guidance has therefore moved toward full replacement of both sides at once, which requires coordinating with each property owner individually.
Coordination is slower in areas with rental housing, absentee owners or language barriers, so replacement pace can vary block by block within one city.
Cost allocation is the unresolved question
Full replacement is expensive, and who pays for the private portion differs by state and by utility, with arrangements ranging from full public funding to owner cost-sharing.
Where owners must contribute, uptake tracks ability to pay, which can leave lead lines concentrated in exactly the households least able to fund removal.
Federal requirements for inventories and replacement have been revised in recent years and continue to develop, so residents should consult their own water utility for the current position on their address.