Arizona’s Maricopa County Board of Supervisors voted in favor of modernizing county zoning rules, a move that will bring clarity to which districts' data centers are allowed in, as reported by the Phoenix Business Journal.

The county’s new ordinance, passed Dec. 10, states that data centers will be allowed in two districts: IND-2 for general industrial uses and IND-3 for heavy industrial uses.

It also states that land not currently zoned for data centers must go through the county’s rezoning process to gain special approval.

Maricopa County is home to 4.5 million people, according to 2022 census data, and is the fourth-most populous county in the nation.

The new rules come amid growing public pushback against suggested data centers in the state.

Last week, the Chandler City Council rejected a rezoning proposal and development agreement for the Price Road Innovation Campus, a 433K SF artificial intelligence data center.

In nearby Pinal County, officials gave preliminary approval to three data center projects on some 3,900 acres this past month. Tucson officials rejected a $3B data center plan in August.

In both the county and the country, concerns are growing about planned data centers due to environmental impact and power usage. Political analysts say those concerns have swayed the outcome of some key off-year elections, including in Virginia and Georgia.

However, the Phoenix metro area has been witness to a slew of successful data center proposals in recent months, including rezoning for a $25B project on the 2,000-acre Hassayampa Ranch center just outside of Buckeye and the $10B construction of a 500-acre Energy Generation and Technology Campus just south of Maricopa.

More than 125 data centers currently operate in Maricopa County, according to ABC News.

Some of the already established centers in the region include EdgeCore’s 3.1M SF campus in Mesa and Expedient’s 46K SF facilities in Phoenix.

Mesa and Phoenix reportedly updated their zoning policies around data centers earlier this year, the PBJ reported.