A service line material unknown letter means your water utility’s records do not show what the pipe into your home is made of. It does not mean the line is lead or that lead was found in your water. Utilities must list every service line and write to owners whose line is lead, galvanized or unknown.
The letters come from the EPA’s revised Lead and Copper Rule, which requires water systems to keep an inventory of service lines, the pipes from the water main to each home. A Dallas city memo dated October 2, 2026 says about 200,000 customers whose line is still listed as unknown will get this year’s notice in October and November. Dallas Water Utilities says the property owner is responsible for the private side, the same split DFW cities use for the water line from the meter to the house.
Start with the pipe where it enters the house. A magnet sticks to galvanized steel. Lead scratches to shiny silver with a key, and a magnet will not stick to it, the same checks used to decide which old plumbing pipes should be replaced. If your utility offers a survey, as Dallas does, report what you find and add a photo. Meanwhile, the EPA advises a filter certified to remove lead, and a water test shows what your tap actually delivers. Dallas offers free lead testing on request through 311.
One honest limit: the pipe you can see at the house may not match the buried section between the meter and the foundation, which may have been repaired with a different material. Only the utility’s records or digging up the line confirm the whole run, which is why Dallas also uses historical records, field investigations and predictive modeling to fill in its inventory.