Water has been flowing from Norton’s faucets in a range of colors, from pale yellow to dark brown, and Senator Elizabeth Warren has now requested that the US Environmental Protection Agency take a look into why.

Warren sent a letter to the agency Thursday urging it to work with the town to determine the cause of the discoloration and whether the water still meets health standards, according to a statement from Warren’s office.

The discoloration has alarmed several residents who are not convinced that the issue is a natural part of the town’s water flushing program, as Norton Water Superintendent Bernie Marshall says it is. Water discoloration is normal when hydrants are flushed, he said.

“The residents of Norton deserve nothing short of absolute confidence in the quality of their drinking water,’’ Warren said in her letter.

Warren’s office didn’t immediately return a message seeking comment on why Norton’s case had drawn her attention.

Marshall said his office had been in contact with the EPA and the Massachusetts Department of Environmental Protection to discuss the issue, which cropped up in September when the town began its biannual water-flushing program.

“We’re introducing cleaner water into the area by flushing’’ sediment that builds up in the town’s pipes, discoloring the water, he said. During the flushing process, residents could end up with less-than-clear water in their faucets as it makes its way out of the system.

If that happens, Marshall said, they should report it to his department, and officials will check for sediment and flush it out of the pipes.

“All they have to do is call our office and we dispatch a technician to their area,’’ he said.

The flushing usually ends around Thanksgiving when the weather turns cold, Marshall said.

The sediment changing the color of the water is mostly flushed out, and the town has been hearing fewer reports of discolored water in recent weeks, he said. They’re also in the process of constructing a treatment facility to reduce the levels of manganese in the town’s water so when they do flush the pipes, the water will not contain the sediment that turns it yellow and brown.

Marshall said these steps will resolve the issue and said residents shouldn’t worry about the town’s water being unsafe.

“At this time, I don’t believe it’s necessary,’’ he said of Warren’s request to the EPA. “Norton is not the only area that has this issue, and we’re in full compliance with the health standards.’’

Alyssa Meyers can be reached at alyssa.meyers@globe.com. Follow her on Twitter @ameyers_.