Building Setbacks & Zoning in Boise, ID

If you live in Boise or are thinking about moving there, building setbacks & zoning are one of those things you probably won't think about until they affect you directly. Boise has 3 specific rules on the books covering different aspects of building setbacks & zoning, and some of them might surprise you.

Setback Rules

Boise sets minimum front, side, and rear yard setbacks by residential zoning district, from 10-foot rears in R-3 to 20-foot fronts and rears in R-1A.

Key details: R-1A/R-1B front (main structure): 15 ft. R-1A/R-1B interior side: 10 ft. R-1C/R-2/R-3 interior side: 5 or 10 ft. R-1A/R-1B rear: 20 ft. Rear on an alley: reduced to 5 ft.

Building Permit applications that don't meet the table's setbacks are rejected until plans are revised or a variance/adjustment is approved; structures built in violation are subject to code enforcement action and can be ordered altered or removed.

Structure Height Limits

Boise's Development Code sets a flat 35-foot cap on new houses in the R-1A and R-1B districts, rising to 40 feet (3 stories) in R-1C, 45 feet (4 stories) in R-2, and 50 feet (4 stories) in R-3. Height is measured as the vertical distance from grade to the highest point of the roof, with narrow, listed exceptions for rooftop equipment and antennas.

Key details: R-1A / R-1B max height: 35 ft.. R-1C max height: 3 stories, 40 ft.. R-2 max height: 4 stories, 45 ft.. R-3 max height: 4 stories, 50 ft.. Height measured: grade to highest roof point.

Height compliance is checked during the City's plan review and building permit process, not after the fact. A house or addition drawn above its district's Table 11-02 cap, and not covered by a Table 11-04.5 exception, cannot receive a building permit or Zoning Compliance approval from the Planning Division until the design is revised or the applicant obtains a variance for undue hardship. Structures built without that approval are subject to the City's standard zoning enforcement and correction process administered by Boise's Planning and Development Services.

Lot Coverage Limits

On Residential Small Lots under 3,500 square feet and on substandard lots of record citywide, Boise limits residential floor area to 70 percent of the effective lot area, with below-grade space excluded from the count.

Key details: Max floor area: 70% of effective lot area. Applies to: lots under 3,500 sf (R-2/R-3). Also applies to: substandard original lots of record. Excluded: below-grade floor area. Min open space: 200 sf/unit, 25% permeable.

Building permit applications that exceed the 70 percent floor-area limit are rejected by Planning and Development Services; building without a compliant permit can trigger a stop-work order and forced modification.

The Bottom Line

Boise's building setbacks & zoning rules are a mixed bag. Some areas are strict, others are relaxed, and the details matter. The best approach is to check the specific rule that applies to your situation rather than assuming Boise is broadly strict or permissive.

These rules come from Boise's publicly available municipal code. For complete penalty schedules, exemption details, and answers to common questions, see the individual ordinance pages throughout this guide.