Purpose and Intent
The RM District is established to accommodate medium density residential neighborhoods. The RM District is intended to allow for, and encourage, an expanded range of housing densities and types to increase residential choices in the city. New development in the RM District shall be thoughtfully integrated, walkable, and interconnected to services and amenities. Infill development in the RM District shall complement existing housing in accordance with the location requirements indicated in Article IV, Sections 18-304, 18-305, 18-307, 18-308, and 18-314 and provide appropriate transitions to adjacent existing neighborhoods including massing, orientation, and scale.
Summary of Allowable Uses
Please refer to Section 18-168 for a complete list of principal uses; Section 18-334 contains a list of accessory uses; and Section 18-366 contains a list of temporary uses.
Legend:
- (SUP): Special Use Permit required
- (L): Limited use standards apply
- (TUP) Temporary Use Permit required
Note: If no item in the legend is listed next to a listed land use, it is permitted by right in the RM district
Main Uses
Agriculture and Animal Related Uses
- Community Garden
- Crop Production (L)
Commercial Uses
No land uses listed
Entertainment Uses
- Cultural and Arts Facility (SUP)
- Private Entertainment / Recreation / Fitness Facility, Indoor (L)
Industrial, Automotive, and Transportation Uses
- Mining (SUP)
- Recycling Collection Center (L)
- Transit Passenger Shelter
- Transit Station (SUP)
- Well / Production Sites
Lodging Uses
No land uses listed
Public and Institutional Uses
- Cemetery / Mausoleum (SUP)
- Civic Meeting Facility (SUP)
- Day Care Facility (SUP)
- Group Home
- Institutional Residential, Assisted Living and Long-Term Care (SUP)
- Library (SUP)
- Park
- Post Office (SUP)
- Public Entertainment / Recreation Facility (SUP)
- Public Service / Safety Facility
- Recovery Residence
- Religious Institution
- School, Public or Private (SUP)
Residential Uses
- Cottage Housing (single lot) (L)
- Duplex (single lot)
- Dwelling, 1 Unit Detached (single lot)
- Dwelling, 2 Units Attached (1 unit per lot)
- Dwelling, 3-8 Units Attached (1 unit per lot)
- Triplex/Quadplex (single lot)
Utilities and Infrastructure Uses
- Public Utility Facilities
- Utility or Government Installation Other than Listed (SUP)
- Water Treatment Plant, Reservoir and Water Storage Tanks
- Wireless Telecommunications, Tower and Equipment (SUP)
Accessory Uses
- Accessory Building / Structure
- Accessory Commercial Unit (L)
- Accessory Community Center, Private (SUP)
- Accessory Dwelling Unit
- Accessory Game Court, Private (SUP)
- Accessory Outdoor Storage
- Amateur Telecommunications Facility
- Golf Safety Net (SUP)
- Home Occupation
- Private Stables (SUP)
- Short-Term Rental
- Solar Energy Collection System, Canopy
- Solar Energy Collection System, Ground-Mounted
- Solar Energy Collection System, Roof-Mounted
- Swimming Pool, Private
- Urban Garden
- Wind Energy Conversion Systems
- Wireless Telecommunications, Building/Structure Mounted (L)
Temporary Uses
- Seasonal Sales
- Special Event
- Temporary Concrete or Asphalt Batch Plant
- Temporary Grazing
- Temporary Parking Lot
- Temporary Use, Other
Development Standards:
To access the complete development standards for the RM zone district, use this link to Section 18-77 of the Code.
Table 18-77.1. RM District dimensional standards by use.
| Regulation | Dwelling, 1 Unit Detached (with alley access or no vehicular access) | Dwelling, 1 Unit Detached (with front vehicular access) | Duplex / Triplex / Quadplex; or Dwelling, 2 Units Attached Dwelling, 3-8 Units Attached (with alley access or no vehicular access) | Duplex / Triplex / Quadplex; Dwelling, 2 Units Attached; or Dwelling, 3-8 Units Attached (with front vehicular access) | Cottage Housing
(with or without alley vehicular access) | All Other Uses (with or without alley vehicular access) |
|---|---|---|---|---|---|---|
| Lot Area, Minimum per Dwelling Unit (square feet) | 2,000 [1] | 3,500 [1] | 1,000 | 2,000 | 2,000 | N/A |
| Lot Width, Minimum per Dwelling unit (feet) [2] | 25 | 50 | 15 | 30 | N/A | N/A |
| Front and Street Side Setback, Minimum (feet) | 10 [1] | 10/20 [1] [3] | 10 [1] | 10 / 20 [1] [3] | 15 | 15 |
| Interior Side Setback, Minimum (feet) | 3 | 5 | 5 [4] | 5 [4] | 10 [5] | 10 [5] |
| Rear Setback, Minimum (feet) [6] | 10 / 0 | 15 / 5 | 10 / 0 | 15 / 5 | 10 | 20 |
| Building Height, Maximum (feet) [7] | 45 / 16 | 45 / 16 | 45 / 16 | 45 / 16 | 45 / 16 | 35 / 16 |
| Lot Coverage, Maximum (%) | 90 | 90 | 93 | 93 | 80 | 80 |
Table 18-77.1 footnotes:
- See Sections 18-573(d) and (e) and 18-574(d) and (e) for setback and minimum lot area reductions in green court and motor court configurations.
- Lot width for front-loaded dwellings can be reduced to match the alley-loaded dwellings if shared driveways are used.
- The first number applies to a porch with or without living space above or to the building if there is no porch. The second number applies to front-loaded garages.
- Standards shall not apply if a fire-related partition wall meeting all Thornton Building Code requirements is provided.
- Ten feet between structures is required unless a fire-rated partition wall meeting all Thornton Building Code requirements is provided.
- The first number is for the principal structure. The second number, if indicated, is for an accessory structure or alley-loaded garage with no driveway.
- The first number is for the principal structure and Accessory Dwelling Units (ADUs) above a garage. The second number is for all other accessory structures.
RM District, Additional Standards
Use this link to Section 18-77(b) to access the additional provisions.
- Required mix of dwelling types. New development in the RM District shall include at least two distinct dwelling types that are permitted uses in this zoning district.
- This requirement shall be fulfilled by the construction of two or more of the following residential options:
- Cottage Housing (single lot) up to eight units;
- Duplex (single lot); or Dwelling, 2 Units Attached (1 unit per lot); or Dwelling, 1 Unit Detached (single lot) with an approved Accessory Dwelling Unit constructed on the same lot at the same time as the Principal Dwelling Unit;
- Dwelling, 1 Unit Detached (single lot);
- Dwelling, 3-8 Units Attached (1 unit per lot); and
- Triplex or Quadplex (single lot).
- The development may be exempt from this requirement if:
- The location of the proposed development does not require at least two distinct dwelling types on the Future Land Use Map based on its Future Land Use Designation in the Comprehensive Plan;
- The total land area of the site proposed to be developed is less than ten acres; or
- The applicant submits an analysis that demonstrates to the satisfaction of the director that the mix of dwelling types will be achieved through existing or planned housing on adjacent parcel.