Where does Phoenix's water come from?
Phoenix gets its water from five main sources: the Colorado, Salt and Verde rivers, groundwater and reclaimed water.
The vast majority comes from the rivers: the Salt and Verde contribute 52%, and the Colorado River 38%. Reclaimed water accounts for 8% of the city's water supply, and groundwater the remaining 2%.
The Salt River Project canals deliver water from both the Salt and Verde rivers, and the Central Arizona Project canals deliver Colorado River water.
Groundwater comes from one of the city's 22 wells, which can pump up 32 million gallons of groundwater per day. State law regulates Phoenix's groundwater pumping through the 1980 Groundwater Management Act because groundwater is a finite resource. It's considered a one-time, non-renewable source because it takes so long to naturally replenish.
Pumping too much groundwater at once has consequences, such as causing land fissures. Phoenix and most other cities try to reduce groundwater pumping and use it only as a backup supply.
Phoenix Mayor Kate Gallego warned at her 2023 state of the city address that Phoenix would dip into its groundwater supply temporarily as it manages upcoming reductions in its Colorado River Supply.
Arizona shares water from the Colorado River with other states through a federal agreement that expires in 2026. Since a future agreement will likely mean less water for Phoenix, the city's newest endeavor is to purify reclaimed water to make it drinkable, effectively adding a water supply that didn't previously exist by recycling it.
Phoenix currently uses reclaimed water, or wastewater, for non-potable uses, meaning not for drinking for agricultural uses and to cool the Palo Verde Nuclear Generating station. It's also injected back into the ground through a process called recharge.
In the future, Phoenix plans to purify reclaimed water to drinking water standards. Plans for an advanced water purification plant at the city's existing 91st Avenue wastewater treatment plant southwest of downtown are underway. The plant would purify 60 million gallons per day — enough water for about 200,000 households per year.
The new supply from the purification facility could replace half of what Phoenix gets from the Colorado River water each year, although Phoenix plans to share the purified water with other cities that buy in. The more Phoenix reduces its reliance on the Colorado River, the more breathing room it and other cities stand to potentially gain.
This article originally appeared on Arizona Republic: Where does Phoenix source its water
