MILWAUKEE — Milwaukee, not Oak Creek, will sell Lake Michigan water to the City of Waukesha under a new deal.

Milwaukee Mayor Tom Barrett and Waukesha Mayor Shawn Reilly announced the 40-year water supply agreement on Monday.

Waukesha Water Utility General Manager Dan Duchniak says for Waukesha, the total cost of connecting to Milwaukee is nearly $40 million less than going to Oak Creek. That’s mainly due to the shorter length of water pipeline needed for the service.

Duchniak says half the cost savings, or $20 million, was achieved through Milwaukee’s offer to pay for building a portion of the new pipeline.

The Milwaukee Journal Sentinel reports lake water will begin flowing west to Waukesha in 2022 or 2023. Waukesha needs a new water source because its groundwater is contaminated with radium.