Attachment C - Zoning Administrator Determination Letter for Large Scale Data Centers(PDF, 346KB)

— Regular Meeting (2026-05-06)

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Planning and Development Services Department (PDSD) - 201 North Stone Avenue  
P.O. Box 27210 - Tucson, AZ 85726-7210 
Telephone: (520) 791-5550 - Fax: (520) 791-4340 
Website: w w w . t u c s o n a z . g o v / p d s d   
 Email:D S D _ Z o n i n g _ A d m i n i s t r a t i o n @ t u c s o n a z . g o v  
September 9, 2025 
 
 
Koren Manning, Interim Director 
Planning and Development Services 
 
Sent via email to: koren.manning@tucsonaz.gov  
  
SUBJECT:   
Zoning Administrator Determination 
Large-scale data centers 
Applicability - Citywide 
Activity # TZ-CMP-0925-00157 
 
Dear Director Manning: 
 
I am in receipt of your email requesting clarification regarding the appropriate land use 
classification for large-scale data centers. This request is also related to directions received 
from the Mayor and Council. 
 
This letter serves as a Determination pursuant to Unified Development Code (UDC) 1.5.1.A 
and the classification of an undefined land use pursuant to UDC 11.3.1.B: “Where a specific 
use does not conform to the wording of any Land Use Class description or conforms to the 
wording of two or more Land Use Class descriptions, the Zoning Administrator shall 
determine the most appropriate Land Use Class for that use. Such a determination is an 
administrative decision.” 
 
Background 
Large-scale data centers have become an increasingly prevalent land use in recent years, 
as technology, computing, and data needs have rapidly shifted. Numerous facilities have 
been built in the Phoenix region. In recent code amendments regarding data centers, 
Phoenix, Chandler, Mesa, and Marana have broadly defined data centers as: 
 
A facility, or a portion of a facility, whose principal use is to store and manage computer 
systems, servers, networking equipment, and components related to digital data 
operations. These operations include the storage, processing, and distribution of digital 
information and may encompass activities related to artificial intelligence, blockchain 
technology, cryptocurrency mining, computational modeling, weather modeling, and 
genome sequencing, among other computationally intensive applications. 
 
The facility typically houses networked computer systems and telecommunications 
equipment used for remote storage, processing, and distribution of data. It also includes 
related infrastructure, office space, and staff areas necessary to support digital data 
 
 
PLANNING AND 
DEVELOPMENT 
SERVICES 
DEPARTMENT  
--------------- 
ZONING 
ADMINISTRATION

Large-scale data centers 
 
Page 2 of 3 
September 9, 2025 
 
Planning and Development Services Department (PDSD) - 201 North Stone Avenue  
P.O. Box 27210 - Tucson, AZ 85726-7210 
Telephone: (520) 791-5550 - Fax: (520) 791-4340 
Website: w w w . t u c s o n a z . g o v / p d s d   
 Email:D S D _ Z o n i n g _ A d m i n i s t r a t i o n @ t u c s o n a z . g o v  
operations. This associated infrastructure can include air handlers, power generators, 
water cooling and storage facilities, and utility substations to support sustained operations. 
A facility is generally not considered a data center if it does not exceed 10% of the gross 
floor area of all on-site buildings, is used to serve the enterprise functions of the on-site 
property owner and is not used to lease data services to third parties. 
 
Analysis 
I have reviewed relevant sections of the UDC and determined that large-scale data centers 
are most directly correlated to a Utilities: Generating System land use, and as such, have 
determined that this is the most appropriate land use class for this use under the current 
UDC. This is based on the following analysis. 
 
When evaluating an undefined land use, the approach is to examine different defined land 
uses and determine the appropriateness of defining the new land use as an existing land 
use. This appropriateness is based upon 1) similarity of the uses and 2) the implied impacts 
based upon the permitted locations and use specific standards. 
 
During the preliminary review, data centers were evaluated as potentially an Industrial, 
Storage, or Utilities land use. Although some characteristics of large-scale data centers can 
be found in numerous other uses, most did not capture the scale and potential impacts of 
the use. The exception being a Generating System land use, which is defined in UDC 
11.3.11.B as: “A facility that produces energy. Typical uses include electrical generating 
plants.” 
 
Although this land use would typically include an electrical generating plant, the intensity 
of large-scale data centers is similar to a Generating System for several reasons. Large-scale 
data centers generate massive amounts of a product to be distributed throughout an 
interconnected system. Like a utility use, they provide a service which is becoming 
increasingly necessary to daily life, but which was not a contemplated use when the current 
UDC land uses were defined. Additionally, large-scale data centers are integrated into 
multiple existing utility systems, including water, electricity, and internet providers, which 
puts a large demand on those utilities.  
 
Generating Systems are not currently permitted by right in any zone but may be permitted 
through establishment of a Planned Area Development (PAD). This indicates that 
Generating Systems are considered a unique land use with potential impacts that may 
require mitigation through the establishment of specialized zoning with community input 
and Mayor and Council approval. The PAD process typically takes 6-12 months from 
submittal to adoption.  
 
Conclusion 
In summary, large-scale data centers will be considered a Generating System land use. Any 
potential data center facility will be evaluated within the broad definition established in

Large-scale data centers 
 
Page 3 of 3 
September 9, 2025 
 
Planning and Development Services Department (PDSD) - 201 North Stone Avenue  
P.O. Box 27210 - Tucson, AZ 85726-7210 
Telephone: (520) 791-5550 - Fax: (520) 791-4340 
Website: w w w . t u c s o n a z . g o v / p d s d   
 Email:D S D _ Z o n i n g _ A d m i n i s t r a t i o n @ t u c s o n a z . g o v  
this letter. Any facility that is an accessory use, also as defined within this letter, will not be 
considered a Generating System. Lastly, any small-scale data center of approximately less 
than 50,000 square feet in size will likewise not be considered a Generating System. 
 
A future UDC code amendment, as directed by Mayor and Council during the study session 
of August 6, 2025, will address large-scale data centers and will establish a defined use, 
appropriate zones, necessary use specific standards, and the approval process for this use. 
Large-scale data centers will likely fall within the Utilities Use Group. This UDC code 
amendment will follow the procedures defined in the UDC which includes a public hearing 
with the Planning Commission as well as Mayor and Council. In addition to the public 
process required by the UDC, PDSD will conduct community engagement to collect input 
which will inform a proposed code amendment to regulate this use. 
 
Should you require further zoning information regarding this matter, please contact me 
via e-mail at Elisa.Hamblin@tucsonaz.gov or my direct telephone number (520) 837-4966. 
 
This determination may be appealed to the Board of Adjustment per UDC Section 1.5.1.E. 
Please contact Mark Castro for questions about the appeal process via email at 
Mark.Castro@tucsonaz.gov or by telephone at (520) 837-4979. 
 
 
 
 
 
 
 
 
 
Sincerely, 
 
 
 
Elisa Hamblin, AICP 
Zoning Administrator