Definitions:

Principal Building
"Principal building" means the specific buildings used for the primary purpose of a property. (e.g. the house and attached decks, patios and porches)

Accessory Building
"Accessory building" means any building or structure which is subordinate in purpose, area, and extent to the principal building and is located on the same lot as the principal building. This includes detached garages, sheds, gazebos, playhouses, and other detached structures including those that do not require a building permit for construction.

Easements

Buildings and structures shall not be located within any easement of record. Buildings and other structures located in easements may be removed or demolished by the easement grantee without reimbursement. Check your title report, property survey, or the property's subdivision map for any easements. 

Easements and setbacks may overlap. Setbacks are not measured from easement lines, only property lines.

Setback Requirement

Structures which are less than 24" above grade may encroach into a required rear or side yard provided such deck
is uncovered and is designed to accommodate lot drainage

Structures which are 24" or more above grade must be placed at or behind the minimum setback distances from the property lines. Setback distances are determined by the zoning district in which the property is located.

If the property is located on a corner, front setbacks apply to both sides that are adjacent to the street.

Zone District Setback from Property Line Requirements

Click to view the Zoning Map

Minimum Setback Standards for Principal Buildings

Residential Single Family

Front yard, dwelling: 15 feet
Front yard, dwelling – alley garage access: 10 feet
Front yard, front-facing garage: 20 feet

Side yard, (no street frontage): 5 feet
Rear yard, without alley: 20 feet
Rear yard, abutting an alley: 6 feet

Residential Mixed Neighborhood

Front yard, dwelling: 15 feet
Front yard, dwelling – alley garage access: 10 feet
Front yard, front-facing garage: 20 feet

Side yard, (no street frontage): 5 feet
Rear yard, without alley: 15 feet
Rear yard, abutting an alley: 6 feet

Residential Multifamily

Front yard, dwelling: 15 feet
Front yard, dwelling – alley garage access: 10 feet
Front yard, front-facing garage: 20 feet

Side yard, (no street frontage): 5 feet
Rear yard, without alley: 10 feet
Rear yard, abutting an alley: 6 feet

Residential Rural

Front yard: 20 feet
Rear yard, no alley: 20 feet
Rear yard, with alley: 6 feet
Side yard: 10 feet

Minimum Setbacks for Accessory Buildings in All Zoning districts
Accessory structures only have one setback: 5 feet. This applies along all the property lines with a caveat: the accessory structure must be behind the front facade of the principal building. That includes both front facades if the property is a corner lot. 

Please note:

• Building codes and site design standards may require setbacks greater than the minimums listed above. Applicants should consult with the Development Services Department prior to development.
• Certain attached features are allowed to encroach into minimum setback distances. Please see LMC §15.03.080.C.10 for all exceptions to setbacks.
• Setbacks must be verified with a survey or surveyed certificate. The Building division accepts Improvement Location Certificates for verification of setbacks for residential developments.

For additional information, please contact Building Inspection at (303) 651-8332 or building.inspection@longmontcolorado.gov