FLINT, MI -- Chloride levels in treated Flint River water are so high that General Motors will no longer use it at its engine plant here because of fears it will cause corrosion.

GM spokesman Tom Wickham said Monday, Oct. 13, that the company has reached a temporary agreement to buy Lake Huron water from Flint Township for Flint Engine Operations on West Bristol Road.

Under the agreement, the plant will return as a Flint water customer after the city switches back to using Lake Huron water -- after the Karegnondi Water Authority pipeline is completed -- something that's not expected to happen until the end of 2016.

"Because of all the metal ... you don't want the higher chloride water (to result in) corrosion," Wickham said. "We noticed it some time ago (and) the discussions have been going on for some time."

The city began using the Flint River as its source of public water in April, ending five decades of buying pre-treated Lake Huron water from the city of Detroit.

The switch has been rocky.

Residents have complained to the City Council about the smell and taste of the river water, the city's Water Treatment Plant has struggled to maintain residual chlorine levels throughout the system, and there were three boil water advisories in a 22-day span this summer after positive tests for total coliform and fecal coliform bacteria.

The Flint Journal could not immediately reach Howard Croft, Flint's Department of Public Works director, for comment on the switch by GM, which uses an average of about 75,000 gallons of water daily at the engine plant.

Mike Prysby, district engineer for the Michigan Department of Environmental Quality, said the level of chloride in treated Flint River water is easily within public health guidelines.

Tests have shown Flint's water in the range of 50 to 60 milligrams of chloride per liter, higher than the level considered excellent, which is less than 20 milligrams per liter, but lower than the level that's considered objectionable, which is higher than 250 millirams per liter.

The city uses ferric chloride, which works as a coagulant, in river water to help remove suspended and dissolved solids and contaminants, according to Prysby.

Flint Township Supervisor Karyn Miller said GM will have to complete work to tie into the township's water distribution system before it can it can start to take in Lake Huron water again.

"It's going to happen as soon as they can (make the connection)," said Miller, who said the township Board of Trustees agreed last week to let the automaker plug into its water network.

"We've already worked something out with GM and GM has worked something out with the city," she said.

Wickham said GM has been coping with the water issue at Flint Engine by further treating the water it receives from Flint and supplementing it with non-river water.

He said no other GM plants in Flint are switching to use a different source of water at this time.

The company operates a stamping plant and truck assembly plant in the same vicinity as the engine plant -- on the southwest side of the city.

Genesee County Drain Commissioner Jeff Wright said his office certified that it has the capacity to supply the water GM needs at the engine plant and is working with the company to connect so that it can become a Flint Township water customer.

Cities and townships around the county make up the county water and sewer system and each bills businesses and residents for water and sewer services.