DETRLOIT, Mich., Dec. 30 (UPI) -- Government leaders and environmentalists are at odds over a federal proposal to allow partially treated sewage into Michigan lakes during heavy rainfall.

The U.S. Environmental Protection Agency says it could save millions but others fear the impact on drinking water, the Detroit News said Thursday.

The EPA is expected to decide by February whether to allow "sewage blending," letting cities to mix untreated sewage with fully treated wastewater during storms.

Predictions are that the policy could save Metro Detroit millions of dollars in sewer repairs and ease basement flooding. But, the plan raises health and ecological fears.

The new rules could send more potentially harmful contaminants into the Detroit River or Lake St. Clair, the source of drinking water for much of the metro area, environmentalists say.

The debate is spurred in part by huge repair bills looming nationwide for aging infrastructure. Southeast Michigan alone faces an estimated $16 billion to $24 billion in sewage upgrades in the next 25 years.