Accessory Dwelling Unit (ADU) Square Footage Standards in the City of Reno
In the City of Reno, the maximum square footage allowed for an Accessory Dwelling Unit (ADU) is determined by the specific residential or multi-family zoning district of the property. For most single-family residential districts, the limit is either 1,200 or 1,600 square feet, but this is further restricted by the size of the principal structure or the rear yard, while higher-density multi-family districts allow up to 2,400 square feet [Section 18.03.405].
Maximum Square Footage Requirements
The City of Reno regulates the size of both attached and detached ADUs by applying the dimensional standards found in the detached accessory structure tables of the land development code. Per City of Reno regulations, an attached ADU must follow the same maximum area standards as a detached ADU [Section 18.03.405(a)(9)(b)].
The following table outlines the maximum allowable square footage for an ADU based on its zoning district:
ADU Size Limits by District
| Zoning District(s) | Maximum Square Footage per ADU | Supplemental Size Constraints |
|---|---|---|
| LLR-2.5, LLR-1, LLR-0.5 (Large-Lot Residential) | 1,600 sq. ft. | Cannot exceed 50% of the principal structure's size |
| SF-3 (Single-Family Residential) | 1,600 sq. ft. | Cannot exceed 50% of the principal structure's size |
| SF-5, SF-8, SF-11 (Single-Family Residential) | 1,200 sq. ft. | Cannot exceed 50% of the rear yard area |
| MF-14 (Multi-Family Residential) | 1,200 sq. ft. | Cannot exceed 50% of the rear yard area |
| MF-21, MF-30 (Multi-Family Residential) | 2,400 sq. ft. | No secondary percentage cap listed |
| GFSF (Greenfield Single-Family Overlay) | 1,200 sq. ft. | N/A |
[Table 3-6, Table 3-7, Section 18.02.603(b)(2)c.4]
Important Size and Configuration Constraints
Beyond the raw square footage numbers, the City of Reno imposes several qualitative and quantitative rules that may further limit the size or placement of an ADU:
Subordination and Image
In the City of Reno, all detached ADUs must maintain a single-family image and be "subordinate to the principal dwelling unit in size, location, and appearance" [Section 18.03.405(a)(10)(a)]. This reinforces the requirement that the ADU cannot be the dominant structure on the lot.
Rear Yard Limitations
For properties in the SF-5, SF-8, SF-11, and MF-14 districts, the "50% of the rear yard" rule is often the primary limiting factor for ADU size. If the rear yard is small, the allowable square footage of the ADU may fall significantly below the 1,200-square-foot maximum [Table 3-7].
Number of Units
The City of Reno prohibits the establishment of more than one ADU on a single lot [Section 18.03.405(a)(3)]. Additionally, an ADU is not considered an "Accessory Dwelling Unit" if it lacks separate and independent cooking (kitchen) facilities; such structures are instead classified as "Guest Quarters" [Section 18.09.302].
Sections Cited
- Section 18.02.603, Neighborhood Planning Area Overlay Districts
- Section 18.03.403, Dimensional Standards for Residential Zoning Districts
- Section 18.03.405, Standards for Specific Accessory Uses
- Section 18.09.302, Accessory Uses