WASHINGTON — The Trump administration on Thursday proposed new regulations on lead and copper in drinking water, updating a nearly 30-year-old rule that may have contributed to the lead-tainted water crisis in Flint, Mich., that began in 2015.

The draft plan, announced by the Environmental Protection Agency administrator, Andrew Wheeler, at a news conference in Green Bay, Wis., includes some provisions designed to strengthen oversight of lead in drinking water. But it skips a pricey safety proposal advocated by public health groups and water utilities: the immediate replacement of six million lead pipes that connect homes to main water pipes. The proposed new rule would also more than double the amount of time allotted to replace lead pipes in water systems that contain high levels of lead.

Mr. Wheeler framed the new regulations as a major step forward in protecting water supplies.

“The water sector has known for years and years that the regulations governing lead and copper in our water need to be improved, but administration after administration has failed to get it done,” Mr. Wheeler said, noting that the standards were last updated in 1991. “We are delivering on the president’s commitment that all Americans have access to clean and safe drinking water.”

Although the new proposal would extend the timetable for replacing lead pipes, it would include new requirements that schools and day care centers be tested for lead, and, if elevated lead levels are found, customers would have to be told within 24 hours, not the current standard of 30 days. It would also require water utilities to conduct inventories of their lead service pipes and publicly report their locations.