County approves 5,157-acre Belmont 4 industrial rezoning

TONOPAH, Ariz. The Maricopa County Board of Supervisors unanimously approved a rezoning that opens approximately 5,157 acres near Tonopah to industrial development, including logistics, manufacturing, data centers, energy production and battery storage.

The October 21 action changes the Belmont 4 property from Rural-43 to General Industrial with an Industrial Unit Plan of Development overlay. The site is north of Indian School Road on both sides of 355th Avenue, about 4.5 miles northeast of Tonopah and 1.6 miles north of the 355th Avenue/Hassayampa Road interchange with Interstate 10.

The approval is a major land-use milestone for western Maricopa County because the property lies along the planned Interstate 11 corridor. It does not approve a construction plan, establish specific tenants or show that site work has started.

Three development areas across more than 5,000 acres

County case Z260020 divides the property into three broad areas.

Approximately 960 acres along and within one-quarter mile of the future I-11 right of way are reserved for a logistics and employment corridor. Allowed uses there include manufacturing, warehousing, distribution and other employment-generating operations. Outdoor heavy-industrial uses are prohibited in that corridor.

Another approximately 4,127 acres make up an Industrial Innovation and Energy Development Area. The applicant’s narrative identifies potential data centers, energy generation and storage facilities, advanced manufacturing, technology campuses and industrial processing. Those are permitted categories, not announced projects.

About 60 acres are set aside as a permanent no-build buffer next to existing residential uses. County conditions require a landscaped setback at least 100 feet wide with berms, native vegetation or other screening.

The zoning allows industrial buildings up to 80 feet tall and energy-production structures up to 150 feet. Maximum lot coverage is 75%, while solar panels, battery-storage containers and certain generation structures do not count toward that calculation.

Water concerns changed before the vote

Water was a central issue in the public record. The Toyota Arizona Proving Grounds is about 11 miles north of the Belmont 4 property in the same Lower Hassayampa basin. An attorney for Toyota initially raised concerns that future groundwater pumping could contribute to subsidence near the proving ground, where Toyota says it has invested more than $500 million.

In an October 19 letter included in the county’s official handout, Toyota said those concerns had been resolved after meetings with the Belmont development team. The letter cited additional information about water planning, acreage set aside for groundwater recharge by Global Water and a commitment to continued communication about water use and recharge.

The project narrative identifies Hassayampa Utility, a Global Water Resources company, as the intended water and wastewater provider. It says approximately 60 acres within the broader Belmont development have already been deeded to the utility for water and wastewater infrastructure.

That does not amount to approval of every future water demand. County conditions require an approved public or private water system and sewer system before a nonresidential use needing potable water can be established. Until sewer service is available, only uses that county environmental and planning officials determine can be served by on-site septic systems may proceed.

Roads and public services remain unresolved

Belmont 4 has no final site circulation plan. Each later Plan of Development must include grading and drainage work and a traffic study. The zoning conditions also require right-of-way dedication or preservation along 355th Avenue, Camelback Road and Campbell Avenue, with additional road improvements to be determined through county transportation review.

The applicant must notify the Arizona Department of Transportation because of the property’s proximity to the future Hassayampa Freeway, the corridor associated with I-11 planning.

Fire and emergency medical service also must be settled before buildings are permitted. The narrative says discussions were underway with the Arizona Fire & Medical Authority and Rural Metro, but no provider had been selected. Written confirmation from the responsible fire jurisdiction is required before a building permit, followed by another approval before occupancy.

What the county approved, and what comes next

The October 21 vote approved the zoning framework and its conditions. It did not approve a site plan, construction permits, utility capacity for a specific user or an I-11 construction schedule.

The applicant anticipates development over the next decade, according to the narrative. Individual projects must return through administrative Plan of Development review before construction permits can be issued. Those later filings will establish building locations, traffic access, drainage, utility service and fire protection.

The most important next records will be the first Plan of Development, utility capacity documentation, traffic studies and any data-center or energy proposal identifying an operator, electrical demand and water use.

Current status: Zoning approved October 21, 2026. No construction plan, tenant, investment total or construction start has been established.

Source records

• Maricopa County Board of Supervisors: October 21, 2026 meeting record (Belmont 4, item 17).
• Maricopa County Planning and Development: Belmont 4 staff report and application materials.
• Maricopa County: October 21 Belmont 4 handout and updated correspondence.
• Maricopa County Board of Supervisors: October 21 meeting video.

Featured image: Original West Valley Post editorial illustration. It is a conceptual, non-site-specific image and does not depict the Belmont 4 plan or current construction.