Service lines connect a city’s water mains to homes and businesses. Today, service lines are usually made with plastic or copper, but the older ones might be lead, cast iron or galvanized steel.

Public water supplies test for lead and make sure the drinking water that leaves their treatment plant meets the EPA’s standards. But if that water later travels through a corroded lead service line, it can pick up some lead and carry it to customers

Large water supplies are required to add chemicals to their drinking water that coat lead pipes, preventing them from corroding and contaminating the water. Still, service lines are the largest source of lead in drinking water across the country.

The Environmental Protection Agency is requiring all public water supplies to inventory their service lines before October 2024, so they can target mitigation projects. Earlier this year, Norman voters approved a water rate increase that will help pay for this lead service line inventory.

“We've got about $6 million in the next five years that we're looking to spend on that program to better understand where we have lead in our system,” said Nathan Madenwald, an engineer with the City of Norman. “So that way, as requirements get more stringent when we're required to do a certain level of replacement per year, we're able to target those projects in those areas where we have lead lines.”

Norman’s survey will look at 250 properties randomly selected from pre-1950s neighborhoods. The city will dig two small holes near the meter box to peek at the service lines and leave an informational door hanger.