Data centers are prohibited as a principal use in all standard Town zoning districts. A principal-use data center may operate only if the Town Council approves a specific plan or specific plan amendment expressly authorizing data-center development through the normal rezoning process.

The specific-plan rezoning process requires Council action and may impose additional or more stringent site-specific requirements reasonably related to the development’s impacts.

Accessory data centers are allowed only in the LI and HI industrial districts and legacy zoning districts, must occupy no more than 15% of the site, must serve the on-site property owner’s enterprise functions, and may not lease data-storage or processing services to third parties.

Applications for a data-center specific plan or amendment must include a baseline noise study and noise-contour exhibit, confirmation from the electric utility that sufficient power is available, an assessment of future energy needs, estimated annual water consumption, confirmation of sufficient water resources, and an explanation of compliance with the ordinance or requested waivers.

Data centers must comply with maximum noise levels measured at affected property lines: 55 dBA day and night for residential or mixed-use properties, 60/55 dBA for agricultural properties, 65/60 dBA for commercial properties, and 72/65 dBA for industrial properties.

A qualified third-party acoustic engineer must conduct pre-construction and post-construction noise studies. Sound-mitigation design specifications are required before building-permit approval, and a permanent certificate of occupancy may be withheld if post-construction noise exceeds the applicable limits.

Data-center operators must conduct additional noise studies annually during peak mechanical-equipment operation for five years after the initial post-construction study and thereafter when requested by the Town; noncompliance requires corrective sound mitigation.

The Marana water department may not provide potable water for a data center’s cooling, humidity-control, or similar operations. The developer must demonstrate an alternate water source.

Data-center buildings, cooling and ventilation equipment, generators, and other power-supply equipment must be set back at least 400 feet from adjacent residential or other noise-sensitive property lines and at least 100 feet from adjacent property lines for uses other than residential or industrial.

Data centers are subject to screening requirements for loading docks, service entries, substations, and mechanical equipment. Mechanical equipment adjacent to residentially planned or zoned property must be screened on all four sides by an acoustical barrier, and ground-mounted mechanical equipment is prohibited in front yards.

Side and rear yards of data-center sites adjoining nonindustrial property must provide landscape buffers: at least 50 feet for agricultural or commercial property and at least 100 feet for residential or mixed-use property, subject to specified landscaping, berm, vegetation, or equivalent screening standards.

Except for electrical transmission lines carrying 48 kV or more, electric power lines serving data centers must be located underground.

Diesel generators must be Tier IV or newer, generator operation is limited to backup or emergency use except for testing or commissioning, and generator testing is limited to weekdays from 8:00 a.m. to 5:00 p.m., except in emergencies.

Data-center sites may not use chain-link fencing, with or without slatted inserts, or barbed-wire fencing along public or private street frontages.

Data-center buildings are generally limited to 55 feet in height, with up to 10 additional feet for screened rooftop mechanical equipment; separate height limits must be specified for substations, utility infrastructure, and accessory communication towers in the specific-plan application.

Data-center buildings must meet detailed architectural standards, including façade modulation and recesses, at least 20% fenestration on each principal façade, a differentiated main entrance, neutral exterior colors, limits on disparate primary materials, and at least five specified architectural features.

Ordinance No. 2024.029 does not become effective until the 31st day after adoption, delaying the operation of the new data-center zoning provisions until that effective date.

Accessory data centers are allowed in the LI and HI industrial zoning districts without requiring approval as a principal use, subject to the ordinance’s conditions.

Accessory data centers are also allowed in Marana’s legacy zoning districts, subject to the same conditions applicable to accessory data centers.

An accessory data center may occupy up to 15% of the site, provided it serves the on-site property owner’s enterprise functions and does not lease data storage or processing services to third parties.

Principal-use data centers may be approved through a specific plan or specific plan amendment, rather than being categorically prohibited.

A specific plan may authorize data center development in a specific geographic area or in a region of a larger specific-plan area, allowing the approval to cover more than one limited site or area.

The Town Council may waive one or more of the ordinance’s minimum requirements during the specific-plan rezoning process if the applicant explains why compliance is not feasible.

The ordinance imposes no maximum lot-coverage limit for data center development.

Data center buildings may be up to 55 feet high, with an additional 10 feet allowed for screened rooftop mechanical equipment.

The 55-foot building-height limit does not apply to utility substations, related utility infrastructure such as utility poles, or accessory communication towers, although the specific plan must establish height limits for that infrastructure.

If a completed data center exceeds the applicable noise limits, the Town may issue a temporary certificate of occupancy while the operator implements the required sound mitigation; a permanent certificate is withheld only if compliance is not demonstrated before the temporary certificate expires.