Costing a lead service line replacement takes a count of the lead lines and a count of the ones nobody has identified. The second is usually larger and it decides the budget, because an unknown line has to be visited before it can be ruled out.
Every US community water system had to file a service line inventory with its state by 16 October 2024. This page is about how much of that record is readable.
What twenty states published
Most is a program page: the rule, the deadline, the filing template. That establishes a state runs a program, and it is not data.
One state publishes a downloadable inventory with a row per line, New York, and it is the only one here these pages can read.
California publishes an inventory nobody can retrieve. The links resolve and the files are real, but the first is about 344 megabytes, served without declaring its size, and every attempt to read it timed out.
Four states refuse automated requests: Louisiana, Massachusetts, Michigan and Colorado. Two have no confirmable inventory address at all, Texas and Georgia, both of which file the water loss audits published here.
A national figure built from sources this uneven is not evenly evidenced, and the differences do not cancel.
New York, the one that can be read
4,618,115 service lines, read on 16 September 2026 from the state’s Lead Service Line Inventory. The state updates it, so a later reading differs.
| what the utility filed | lines | share |
|---|---|---|
| not lead | 2,529,135 | 54.8% |
| unknown | 1,798,577 | 38.9% |
| lead | 248,843 | 5.4% |
| galvanized, requiring replacement | 38,352 | 0.8% |
| category was a spreadsheet error | 3,164 | 0.1% |
| no service line at that address | 43 | 0.0% |
| not recognized | 1 | 0.0% |
Two fifths of New York’s service lines have no known material, and that is the figure most likely to be reported away. About half of those rows have an empty material column rather than the word “unknown”. Drop the empties as missing data and the state reports a fifth, wrong by nearly a million lines. An empty cell in a mandated inventory is a line the utility did not categorize, which is what unknown means.
The 3,164 rows whose category is a spreadsheet error are counted apart, never folded into unknown. A spreadsheet that failed and a utility that does not know are different facts, and only one is about pipe.
These are state totals. The inventory does not record which water system a line belongs to, so nothing here is attached to a named utility.