Boulder County Planning Publications
Lot Lines, Setbacks and Yards- P21

Publication P21 Yards, Lot Lines and Setbacks, based on the Boulder County Land Use Code, describes the zoning terminology and measurement standards for yards, lot lines, and setbacks as they relate to development on a parcel.

Property Setbacks

A setback is the required minimum distance between a structure and the related front, side, or rear lot line. The setbacks on a parcel can be different depending on the zoning district, whether the parcel is in a subdivision, or when a lot in a subdivision was created. There are also unique situations in which there might be additional setbacks on your property. These include but are not limited to:

• When a road right-of-way encroaches into or through a parcel, the setback is measured from the exterior edges of the road right-of-way instead of the lot line.
• There is a 50-foot setback from the centerline of an irrigation ditch, though this can be reduced to no less than 20 feet with a letter from the owner of the ditch.
• If your property is next to a major road (discussed in more detail below).
• Though most development is required to meet setbacks, there are some types of development that might not be required to meet setbacks (discussed in more detail below).

The required setbacks for each zoning district can be found in the table at the bottom of this page.

Setbacks on Parcels in Subdivisions Created Before Oct. 19, 1994

FRONT: That part of a property line dividing a lot from a road. On a corner lot, only one property line shall be considered as a front line. The shorter property line shall be considered the front unless the property owner chooses another property line dividing the lot from a road.

REAR: The line opposite and parallel to the front line. In the event no lot line is opposite and parallel to the front lot line, there shall be no rear lot line.

SIDE: All lot lines other than front lot lines or rear lot lines. A triangular lot has two side lot lines and no rear lot line.

Setbacks for Parcels that are not in Subdivisions OR are in Subdivisions Ceated After Oct. 19, 1994

FRONT: That part of a property line that divides a lot from a road, exempting private thoroughfares which are not in subdivided land. On a corner lot or other lots with multiple frontages, all street frontages shall be governed by front yard regulations.

REAR: The boundary line opposite and parallel to the front line. In the event no lot line is opposite and parallel to the front lot line, there shall be no rear lot line.

SIDE: All lot lines other than front lot lines or rear lot lines. A triangular lot has two side lot lines and no rear lot line.

Additional Requirements for Yards Along Major Roads

The Boulder County Land Use Code defines a yard as the space between a parcel’s lot lines and the nearest point of a structure. The minimum yard for each parcel is created by the required setbacks in a parcel’s zoning district; however, parcels located next to major roads (like freeways, expressways, arterials and collectors) have additional yard setback requirements. If your property is next to a major road, your development will be required to meet the additional setbacks below:

• 160 feet from the centerline of any freeway or expressway;
• 110 feet from the centerline of a principal arterial or minor arterial;
• 90 feet from the centerline of any collector not in mountainous terrain; and
• 55 feet from the centerline of any minor arterial in mountainous terrain.

Cornices, canopies, eaves, or similar architectural features may extend two feet into a required yard. Fire escapes may extend six feet into a required rear yard.

Development not Required to Meet Setbacks

Generally, the following types of development are not required to meet lot line setbacks or the more restrictive setbacks along roads:

• Retaining walls four feet or less in height, measured from the bottom of the footing to the top of the wall, that don’t require a building permit;
• Fences six feet or less in height;
• Any swimming pool that does not require a building permit;
• Platforms or decks 30 inches or less above grade and not over any basement or story below;
• Utility mains, lines, and underground facilities; and
• Yard and play equipment.

Although the above types of development are not required to meet the setbacks in the Land Use Code, they still may be required to comply with ditch setbacks or other easements located on your property.

Zoning District Setbacks

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