ADU Rules in Denver, Colorado

Complete guide to building an Accessory Dwelling Unit in Denver — zoning, setbacks, permits, costs, and more.

Max Size: 864 sq ft Setbacks: Must be within rear 35% of lot; 5 ft minimum rear setback No Parking Required Verified: 2026-02-25
ADU Score: 8/10

Denver is highly ADU-friendly, allowing detached and attached units in most residential zones with streamlined approval. The city's emphasis on infill development and housing affordability makes it one of the nation's better ADU markets.

Zoning & Size Requirements [1][2]

Allowed ZonesAll residential zones
Max Size (Detached)864 sq ft
Max Size (Attached)864 sq ft
Max Size (JADU)800 sq ft
Max Height24 ft maximum
Max Units1 detached + 1 attached per lot

Setback Requirements [1][2]

Rear SetbackMust be within rear 35% of lot; 5 ft minimum rear setback
Side Setback3 feet
Front Setback15 feet
Parking Required1 space per unit
Owner OccupancyRequired in single-unit zones (owner must live in primary or ADU)
Min Lot Size3,500 sq ft

Permit Process & Fees [3]

Approval ProcessMinisterial approval (by-right)
Review Timeline30-45 days
Permit Fees$1,600-$2,700
Impact FeesMinimal
Plan Check1-2 weeks
Pre-Approved PlansExtensive library available

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Construction Costs [4][5]

Average Build Cost$140,000-$280,000
Cost per Sq Ft$130-$260
Garage Conversion$70,000-$160,000
Prefab ADU (Installed)$100,000-$230,000

Finance Your ADU Project

Most ADU projects are funded through HELOCs, construction loans, or cash-out refinancing. Compare rates from top lenders.

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Rental Income Potential [6][7]

Avg Rent (1 Bedroom)$1,400-$1,900/mo
Avg Rent (2 Bedroom)$1,800-$2,500/mo
Short-Term RentalYes, with STR license
Est. Annual ROI7-9% annual return

Explore Prefab ADU Options

Prefab ADUs can save 20-40% vs. traditional construction and cut build time in half.

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Recent Law Changes

What's Changed Recently

  • Denver ADU ordinance expanded (2026): ADUs now allowed on all residential lots citywide
  • Boulder reduced ADU setback requirements to 3 ft for rear structures
  • Colorado Springs streamlined ADU permitting: 45-day review guaranteed (2026)
  • State HB 24-1152 effects: More municipalities adopting ADU-friendly policies

Tips for Building an ADU in Denver

  • Denver's by-right approval means fastest permitting timeline
  • Tech and service industry growth ensures strong rental demand
  • Short-term rental market strong; explore vacation rental opportunities
  • Pre-approved plans available; maximize timeline efficiency

Sources & References

All data on this page is sourced from official government records and verified market data. View our full methodology.

  1. Accessory Dwelling Units (ADUs) in Denver Planning Department — Accessed 2026-02-24
  2. Citywide ADU Zoning Text Amendment Municipal Code — Accessed 2026-02-24
  3. ADU Permits | Denver CPD Planning Department — Accessed 2026-02-24
  4. HomeAdvisor — ADU Construction Cost Data Market Data — Accessed 2026-02-24
  5. Angi — Local ADU Contractor Costs Market Data — Accessed 2026-02-24
  6. Zillow Rental Manager — Market Rent Data Market Data — Accessed 2026-02-24
  7. HUD Fair Market Rents Government Data — Accessed 2026-02-24
  8. Denver ADU Interactive Map Planning Department — Accessed 2026-02-24
  9. Colorado ADU Legislation (HB 24-1152) Government Data — Accessed 2026-02-24

Frequently Asked Questions

Can I build an ADU in Denver?

Yes. ADUs are allowed in All residential zones in Denver. The maximum size for a detached ADU is 864 sq ft. No owner-occupancy is required.

How much does an ADU cost in Denver?

ADU construction in Denver typically costs $140,000-$280,000. Garage conversions run $70,000-$160,000, and prefab ADUs cost $100,000-$230,000.

How much can I rent an ADU for in Denver?

Average ADU rents in Denver are $1,400-$1,900/mo for a 1-bedroom and $1,800-$2,500/mo for a 2-bedroom unit.

Do I need parking for an ADU in Denver?

1 space per unit. Check with Denver planning department for the latest Colorado ADU parking rules, as many states have relaxed requirements in recent years.

How long does it take to get an ADU permit in Denver?

The permit review timeline in Denver is 30-45 days. Fees range from $1,600-$2,700.

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