Phoenix relies on Colorado, Salt and Verde rivers and limited groundwater for drinking water

Lara Van Lyth, volunteer coordinator and water resource specialist for the City of Phoenix Water Services Department, told trainees that Phoenix’s treated drinking water comes from four main sources: the Colorado River, the Salt River, the Verde River and groundwater.

"You can see that we only use 2% of our deliveries from groundwater and the remaining 98% of our deliveries are coming from surface water," Van Lyth said, describing city practice to use groundwater sparingly because recharge is slow.

Van Lyth also said the Colorado River Basin is a regional supply shared across states and nations and that "40% of our drinking water comes from this source." She explained the basin serves seven U.S. states, roughly 30 Indigenous communities and both the United States and Mexico, and supplies water to more than 40,000,000 people.

The training included a geographic overview: the Salt and Verde rivers and local canals feed surface supplies that are treated and distributed, while groundwater functions as a limited reserve. Van Lyth noted the Gila River does not provide Phoenix’s drinking water; runoff from Phoenix ultimately flows into the Gila and then back into the Colorado River system downstream.

The session emphasized watersheds as the landscape units that collect precipitation and route water to rivers, reservoirs, and canals used by cities. Trainees were encouraged to explain these source distinctions when conducting outreach and to use department resources for technical questions.