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Boulder Zoning & Land Use Guide

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Key Zoning Facts

Planning Department
City of Boulder Planning & Development Services(303) 441-1880
Building Code Edition
2021 IBC with Boulder Amendments
ADUs Allowed
Yes
Primary District
RL-1 Residential - Low 1
Max Height
35 ft

Boulder Zoning Overview

Boulder is a city of approximately 106,000 residents located at the base of the Flatirons in Boulder County. The city is home to the University of Colorado and is known for its extensive open space program, which has preserved over 46,000 acres of land surrounding the city. Boulder's zoning code, contained in Title 9 of the Boulder Revised Code, employs a comprehensive district system that addresses the city's unique combination of natural constraints, housing demand, and growth management policies. The city's Residential Growth Management System (also known as the "Danish Plan") has limited the number of new residential building permits issued annually since 1977, making Boulder one of the most growth-managed cities in the West.

Boulder's land use is shaped by its geographic constraints -- the Flatirons and foothills to the west, open space to the north and south, and the Rocky Flats area to the southeast. The city's height limit, originally adopted by voters and now codified as a 55-foot general limit in most areas with lower limits in residential zones, keeps building heights low relative to other cities of similar size. Boulder's planning framework emphasizes sustainability, multimodal transportation, affordable housing, and historic preservation. The Pearl Street Mall and surrounding downtown serve as the city's commercial and cultural center.

Planning and Development Services manages zoning, development review, and building permits. The city's development review process is known for being thorough, with design review requirements in many areas.

Key Zoning Districts

Boulder's residential districts range from RL-1 (very low density, 30,000 sq ft minimum lots) and RL-2 (standard low density) to RM (medium density allowing duplexes and townhomes) and RH (high density allowing apartments). Commercial districts include BMS (Business Main Street), BC (Business Community), and BR (Business Regional). Boulder also has Industrial and Public districts and several environmental and historic overlay zones.

ADU Regulations

Boulder has allowed ADUs for longer than most Colorado cities. Current regulations permit ADUs up to 1,000 square feet and 22 feet in height in residential zones. Boulder's local regulations supplement Colorado HB 24-1152, with design compatibility requirements and a more involved review process. Owner-occupancy of either the primary dwelling or ADU is required. Permits typically take six to ten weeks.

Development Process

Boulder's development review process includes concept review, site review, and building permit stages. Many projects require design review, particularly in the downtown, university hill, and historic areas. The Planning Board reviews major projects, while administrative staff handles minor applications. Building permits are processed by the Building Services Center, with timelines that vary based on project complexity.

Regulatory Layers That Apply in Boulder

Your property is subject to ALL of these regulatory layers. Each one can impose additional requirements beyond the others.

Federal

State — Colorado

  • Building Code: 2021 IBC (locally adopted)
View Colorado zoning overview

County — Boulder County

  • Role: Property records, tax assessment, unincorporated area planning

City / Municipal

The city's zoning ordinance, building codes, and local permits form the primary layer of land-use regulation for your property.

Overlay Districts

No overlay districts identified.

Private Restrictions

  • HOA / CC&Rs common: Yes
  • Check HOA CC&Rs for additional restrictions.

Primary Zoning Districts

RL-1Residential - Low 1
Min Lot
30,000 sq ft
Max Height
35 ft
Front Setback
25 ft
Side Setback
10 ft
Rear Setback
25 ft
RL-2Residential - Low 2
Min Lot
7,000 sq ft
Max Height
35 ft
Front Setback
20 ft
Side Setback
5 ft
Rear Setback
15 ft
BMSBusiness - Main Street
Min Lot
None
Max Height
35-55 ft
Front Setback
0 ft
Side Setback
0 ft
Rear Setback
10 ft

ADU Rules in Boulder

ADUs:Allowed
Max Size
1,000 sq ft
Max Height
22 ft
Rear Setback
5 ft
Side Setback
5 ft
Parking
No additional parking required
Owner Occupancy
Required for either primary or ADU
Permit Timeline
6-10 weeks

Permit Costs & Timelines

Permit Costs & Timelines

Specific permit fee schedules for Boulder are available from the local planning department. Fees vary based on project type, scope, and valuation.

Check Boulder permit fees →

Official Sources

Frequently Asked Questions

Can I build an ADU in Boulder?
Yes. Boulder allows ADUs in residential zones, with local regulations supplementing Colorado HB 24-1152. Boulder has permitted ADUs for many years, and its regulations address size, height, and design compatibility.
How do I find the zoning for my property in Boulder?
Use the City of Boulder's online zoning tool through the Planning & Development Services website, or call (303) 441-1880.
What zones allow multi-family housing in Boulder?
Multi-family housing is allowed in Residential Medium (RM) and Residential High (RH) districts, as well as Mixed Use and Business districts.