PHOENIX (AP) — The cities of Phoenix and Avondale have reached a deal that will allow Phoenix to store excess Colorado River water in Avondale's underground aquifers for use during a drought.

The agreement announced Wednesday is designed to give both cities wiggle room during a water shortage.

During normal water years, Avondale will draw treated drinking water from an interconnection with Phoenix using its share of Colorado River water. At the same time, Phoenix will send some of its untreated Colorado River water to Avondale for percolation into its aquifers.

During shortages, Avondale can pump that water for its needs and Phoenix can use an equal amount of Avondale's Colorado River water.

Avondale could store enough water by the end of 2018 to serve nearly 7,000 average households for a year.