Pennsylvania American Water asked state regulators on Monday to approve a plan to spend about $6 million a year to replace customers' lead service lines. The utility would recover the costs with a surcharge on every customer amounting to about 11 cents a month.

The utility estimates that about 18,000 of its 656,000 customers still have lead pipes connecting their houses to water mains, which have been linked to elevated levels of the metal in drinking water. Though customers are responsible for maintaining and replacing their own service lines, Pennsylvania American has proposed to spread out the cost to address the public-health risk.

"Lead service lines largely remain in older neighborhoods, where the prohibitive costs often prevent homeowners from replacing them," Pennsylvania American president Jeffrey McIntyre said in a statement. "We are asking for PUC approval to address this public-health risk, and we have proposed a reasonable approach to recover the cost of our investments."

In March, the state Public Utility Commission approved an emergency order allowing York Water Co. to charge other ratepayers to replace about 400 lead service lines a year. Pennsylvania American cited the York decision in its request.

The utility said it will replace lead lines it encounters when it is replacing water mains and will also replace lines at customer request, though it says it will try to group requests to complete multiple line replacements as a single project. The utility says it costs about $3,500 to replace a single lateral line.

The lead-pipe surcharge would come on top of a general 16.4 percent rate increase the utility requested last month that would generate $107.9 million statewide.

Pennsylvania American, a subsidiary of American Water of Voorhees, has about 44,000 customers in the Philadelphia suburbs.

Water utilities and regulators have been aggressively addressing concerns about lead in drinking water after the recent public-health crisis in Flint, Mich.