Mesa Residential Small Lot Single Dwelling Districts (RSL-2.5, RSL-3.0, and RSL-4.0)
Mesa’s Residential Small Lot Single Dwelling (RSL) Districts are designed for small-lot single-family residential development with densities reaching up to 17 units per net acre. These districts require a minimum of 400 square feet of open space per dwelling unit and strictly limit building heights to 30 feet to maintain neighborhood compatibility while providing diverse housing options [Section 11-5-1(B)(2), Section 11-5-3(A)(5)].
Purpose and Intent of the RSL Districts
The primary purpose of the RSL-2.5, RSL-3.0, and RSL-4.0 districts in the City of Mesa is to accommodate detached single-dwelling housing on smaller parcels than traditional residential zones. This category is intended to increase the variety of housing types available to residents and ensure that higher-density infill projects remain compatible with the surrounding neighborhood character [Section 11-5-1(B)(2)].
The numerical designators (2.5, 3.0, and 4.0) represent the minimum average lot size in thousands of square feet. For example, RSL-2.5 requires a minimum average lot area of 2,500 square feet [Section 11-5-1(B)(2)].
Permitted Land Uses in RSL Districts
The City of Mesa identifies several primary and accessory uses permitted by right or through specific permits within the RSL-2.5, 3.0, and 4.0 districts.
Residential and Community Uses
- Single Residence: Permitted by right [Table 11-5-2].
- Assisted Living Home (5 to 10 residents): Permitted by right [Table 11-5-2].
- Family Community Residence: Permitted by right [Table 11-5-2].
- Transitional Community Residence: Subject to a Special Use Permit (SUP) [Table 11-5-2].
- Day Care Group Home (up to 10 children): Permitted by right [Table 11-5-2].
- Accessory Dwelling Unit (ADU): Permitted as an accessory use [Table 11-5-2].
Public and Institutional Uses
- Parks and Recreation Facilities (Public): Permitted by right [Table 11-5-2].
- Community Gardens: Permitted by right [Table 11-5-2].
- Places of Worship: Permitted by right [Table 11-5-2].
- Schools (K-12, Public): Permitted by right [Table 11-5-2].
- Schools (K-12, Private): Requires a Council Use Permit (CUP) [Table 11-5-2].
Development Standards
Mesa enforces specific dimensions for the RSL Districts to regulate density, massing, and open space.
Lot and Intensity Standards
| Standard | RSL-4.0 | RSL-3.0 | RSL-2.5 |
|---|---|---|---|
| Min. Average Lot Area (sq. ft.) | 4,000 | 3,250 | 2,500 |
| Min. Individual Lot Area (sq. ft.) | 3,500 | 2,750 | 2,000 |
| Min. Lot Width - Interior (ft.) | 35 | 30 | 25 |
| Max. Building Height (ft.) | 30 | 30 | 30 |
| Max. Lot Coverage (%) | 75% | 80% | 80% |
Yard and Setback Requirements
| Setback Location | RSL-4.0 | RSL-3.0 | RSL-2.5 |
|---|---|---|---|
| Front - Building Wall (ft.) | 15 | 15 | 12 |
| Front - Garage (ft.) | 20 | 20 | 20 |
| Street Side (ft.) | 10 | 10 | 10 |
| Interior Side - Each Side (ft.) | 4 | 4 | 3 |
| Rear (ft.) | 20 | 20 | 15 |
[Source: Table 11-5-3.A.2]
General Character and Supplemental Regulations
The character of RSL neighborhoods in Mesa is defined by compact lot arrangements and mandatory residential amenities.
Open Space Requirements
The City of Mesa requires that RSL developments provide at least 400 square feet of open space per lot. This can be achieved through:
- Private Open Space: Contained entirely on the individual lot (e.g., patios, balconies, or courtyards). No single space can be smaller than 80 square feet [Section 11-5-3(A)(5)(a)].
- Common Open Space: A combination of private space on the lot and shared community space. For RSL-4.0, the requirement is 350 sq. ft. of private space and 100 sq. ft. of common area per lot. For RSL-3.0 and RSL-2.5, it is 280 sq. ft. of private space and 120 sq. ft. of common area per lot [Section 11-5-3(A)(5)(b)].
Building Design and Massing
- Third-Story Structures: While RSL districts generally focus on two-story homes, a third story may be permitted if it is integrated into a pitched roof (minimum 1:3 ratio) and does not exceed 60% of the building footprint [Section 11-5-3(A)(4)].
- Zero-Lot-Line Developments: These are permitted in the RSL districts to allow for more flexible site planning, provided that the side yard on the opposite side meets the minimum aggregate setback [Section 11-5-3(A)(3)(c)].
Parking
Mesa requires two (2) parking spaces per primary dwelling unit. These spaces may be provided in tandem with Zoning Administrator approval. Notably, no additional parking is required for Accessory Dwelling Units in the RSL districts [Table 11-32-3.A].
Sections Cited
- Section 11-5-1: Purpose (Residential Districts)
- Table 11-5-2: Residential Districts Land Use Regulations
- Section 11-5-3: Development Standards for the RS and RSL Districts
- Table 11-5-3.A.2: Development Standards - RSL Residential Small Lot Single Dwelling Districts
- Table 11-32-3.A: Required Parking Spaces By Use