Adding a second dwelling unit#
If you are considering adding a second dwelling unit to your property, there may be options available to you. However, in one residential zone district, more than one dwelling unit is not allowed:
- Low Density Residential District (RL)
You can read more about the Low Density Residential District (RL) starting page 6 of Article 2 of the Land Use Code.
New dwelling units are not allowed in the Poudre River 100-year floodplain. Please check if your property is in this floodplain.
Ways to add a second dwelling unit#
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Accessory Dwelling Unit#
An Accessory Dwelling Unit (ADU) is a small house or unit that is on the same property as a larger building.
An ADU:
- Contains everything someone needs to live in a home: a kitchen, bathroom and living area.
- Is on the same property or lot as another primary dwelling unit.
- Is smaller than the primary dwelling unit and is located to the rear of the primary unit.
- Can be attached to a house or detached.
Accessory Dwelling Units may be permitted on some lots in Fort Collins. They are only allowed where there is an existing detached house, duplex, triplex, or non-residential use operating in a detached house.
The lots where ADUs may be permitted are:
- Any lot 12,000 square feet or larger in the Old Town Low Density (OT-A) Zone District
- Any lot 10,000 square feet or larger in the Old Town Medium Density (OT-B) Zone District
- Any lot that is part of a Residential Cluster in the Rural Lands (RUL) Zone District
- Any lot that is part of a Residential Cluster in the Residential Foothills (RF) Zone District
- Any lot in the following zone districts:
- Community Commercial District (CC)
- Community Commercial - North College District (CCN)
- Community Commercial - Poudre River District (CCR)
- General commercial District (CG)
- Service Commercial District (CS)
- Limited Commercial District (CL)
- Low Density Mixed-Use Neighborhood District (LMN)
- Medium Density Mixed-Use Neighborhood District (MMN)
- High Density Mixed-Use Neighborhood District (HMN)
- Neighborhood Commercial District (NC)
- Downtown District (D)
- Harmony Corridor District (HC)
- Employment District (E)
- Industrial District (I)
- River Conservation District (RC)
It will not be possible to build an ADU on all of the properties that meet the above descriptions due to standards that regulate setbacks, on-site (off-street) parking, utility access, fire access, stormwater mitigation, and possibly others.
Please see the Land Use Code for more detailed regulations.
More resources on ADUs#
![Drawing of a house on a lot with a smaller house behind it it the rear yard.]()
If you are considering building an ADU on your property, please visit our ADU resource page to learn more.
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A Second Detached House#
A Second Detached House
In some zone districts, two or more detached houses may be permitted on a lot. Some of these zone districts have density limits that may restrict the number of houses on a lot.
- Rural Lands District (RUL)
- Residential Foothills District (RF)
- Community Commercial District (CC)
- Community Commercial - North College District (CCN)
- Community Commercial - Poudre River District (CCR)
- General commercial District (CG)
- Service Commercial District (CS)
- Limited Commercial District (CL)
- Low Density Mixed-Use Neighborhood District (LMN)
- Medium Density Mixed-Use Neighborhood District (MMN)
- High Density Mixed-Use Neighborhood District (HMN)
- Neighborhood Commercial District (NC)
- Downtown District (D)
- Harmony Corridor District (HC)
- Employment District (E)
- Industrial District (I)
- River Conservation District (RC)
It will not be possible to build a second dwelling unit on all of the properties in the above zone districts due to standards that regulate setbacks, on-site (off-street) parking, utility access, fire access, stormwater mitigation, and possibly others.
Please see the Land Use Code for more detailed regulations.
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Duplexes#
A duplex is a single building containing two dwelling units. Also known as a two-unit dwelling, the property is owned by one entity.
Duplexes are permitted in the following residential zone districts:
- Urban Estates (UE) Zone District,
- Old Town Medium Density (OT-B) Zone District
- Rural Lands District (RUL) - only in a Residential Cluster
- Residential Foothills District (RF) - only in a Residential Cluster
Duplexes are permitted in the following mixed-use zone districts:
- Low Density Mixed-Use (LMN) Zone District
- Medium Density Mixed-Use (MMN) Zone District
- Old Town High Density (OT-C) Zone District
- Downtown (D) Zone District, including:
- Canyon Ave./Civic/North Mason Subdistrict
- Campus North (DCN) Subdistrict
- Entryway Corridor (DEC) Subdistrict
Duplexes are permitted in the following commercial and employment zone districts:
- Community Commercial (CC) Zone District
- Community Commercial - North College (CCN) Zone District
- Community Commercial - Poudre River District (CCR) Zone District
- General Commercial (CG) Zone District
- Service Commercial (CS) Zone District
- Neighborhood Commercial (NC) Zone District
- Limited Commercial (CL) Zone District, including:
- Riverside Area
- All other areas
- Harmony Corridor (HC) Zone District
- Employment (E) Zone District
It will not be possible to build a duplex on all of the properties in the above zone districts due to standards that regulate setbacks, on-site (off-street) parking, utility access, fire access, stormwater mitigation, and possibly others.
Please see the Land Use Code for more detailed regulations.
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Single Unit Attached Dwellings#
A single unit attached dwelling is a single building containing multiple dwelling units. Sometimes known as a townhome, rowhouse or a patio home, the building and property it is built on are divided into units owned by individual entities.
Single unit attached dwellings are permitted in the following residential zone districts:
- Rural Lands District (RUL)
- Urban Estates District (UE)
- Residential Foothills District (RF)
- Old Town Medium Density District (OT-B)
Single unit attached dwellings are permitted in the following mixed-use zone districts:
- Low Density Mixed-Use (LMN) District
- Medium Density Mixed-Use (MMN) District
- Old Town High Density District (OT-C)
- Downtown (D) District, including:
- Canyon Ave./Civic/North Mason subdistrict
- Innovation/River subdistrict
- Campus North subdistrict
- Entryway Corridor subdistrict
Single unit attached are permitted in the following commercial and employment zone districts:
- Community Commercial (CC) District
- Community Commercial - North College (CCN) District
- Community Commercial- Poudre River (CCR) District
- General Commercial (CG) District
- Service Commercial (CS) District
- Neighborhood Commercial (NC) District
- Limited Commercial (CL) District, including:
- Riverside Area
- All other areas
- Harmony Corridor (HC) District
- Employment (E) District
It will not be possible to build a single unit attached dwelling on all of the properties in the above zone districts due to standards that regulate setbacks, on-site (off-street) parking, utility access, fire access, stormwater mitigation, and possibly others.
Please see the Land Use Code for more detailed regulations.
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Subdividing a Property#
In some cases it may be possible to add a second dwelling unit by subdividing a property and putting the second unit on the newly-created parcel. This may be possible on properties in the RUL, RF, and RL Zone Districts, that only allow one dwelling unit on a property.
Residential zone districts have minimum lot sizes and minimum lot widths that will preclude this option in most cases. Please see our page on subdividing properties for more information.
Zone District Minimum lot area Minimum lot width Rural Lands District (RUL) 10 acres 200 feet Urban Estates District (UE) 1/2 acre 100 feet, OR
60 feet if the subdivision was developed prior to March 28, 1997Residential Foothills (RF) 100,000 square feet (2.29 acres) 200 feet Residential Low Density (RL) 6,000 square feet, OR
3 times the total floor area of the buildings, whichever is larger60 feet Old Town Low Density (OT-A) 6,000 square feet 40 feet Old Town Medium Density (OT-B) 5,000 square feet for a detached house or duplex.
6,000 square feet for all other uses40 feet for a detached house or duplex.
50 feet for all other uses.Old Town High Density (OT-C) None 40 feet for a single-family house or duplex.
50 feet for all other uses.Low Density Mixed-Use Neighborhood (LMN) None,
But only up to 1 dwelling unit per 4,840 square feetNone Medium Density Mixed-Use Neighborhood (MMN) None None Downtown (D) None None Please see the Land Use Code for more detailed regulations.
Ready to get started#
The City offers free Conceptual Design Review meetings where you can submit an idea or proposal about adding a second dwelling unit and receive feedback and fee estimates and process information.
This is would be done prior to formally submitting an application.