ADU Permits & Zoning in Denver: What Homeowners Need to Know

If you’re thinking about building an Accessory Dwelling Unit (ADU) in Denver or the surrounding metro area, one of the first hurdles you’ll face is understanding the permitting and zoning process. It can feel confusing—but it doesn’t have to be.

At Denver Dream Builders, we’ve helped dozens of homeowners successfully navigate city regulations to build legal, high-quality ADUs. Below are the 10 most common questions we hear about ADU permits and zoning—with detailed answers to help you move forward with confidence.

1. Do I need a permit to build an ADU in Denver?

Yes. All ADUs in Denver require building permits—and the type of permit depends on whether you’re building new construction, converting a garage, or remodeling a basement. You’ll need to submit architectural plans, site surveys, and possibly neighborhood notifications. It’s not a simple DIY permit process—but we handle it for you.

2. Is my property even zoned for an ADU?

Not all Denver properties are zoned for ADUs. You’ll need to check if your lot has ADU zoning (like U-SU-A1, E-SU-D1x, etc.), which determines if you’re allowed to build one. This info is public and available via the Denver Zoning Code or interactive maps. We run zoning checks for all our clients before any design work begins.

3. Can I rezone my lot if it’s not currently ADU-eligible?

Yes—but it’s a process. Rezoning involves submitting a formal application to the city, attending public hearings, and getting approval from both the planning department and city council. It can take several months and costs money upfront—but if your neighborhood has started trending toward ADU acceptance, it may be worth pursuing.

4. What are the key zoning restrictions I need to know?

Denver zoning code places limits on:

• Building height
• Total square footage
• Placement on the lot (setbacks)
• Detached vs. attached structure
• Occupancy (owner must live on site)

We interpret these for your specific lot so you’re not stuck in analysis paralysis or facing costly redesigns.

5. What’s the difference between a detached ADU and an internal one?

Detached ADUs are built separately from your main house—like a backyard cottage or converted garage. Internal ADUs are created within your existing home or basement. Zoning and permit requirements can vary between the two, especially when it comes to height limits and fire separation.

6. Do I need approval from my HOA?

If you live in a neighborhood governed by an HOA, yes—you’ll likely need approval before moving forward. HOA rules can restrict the design, height, appearance, or even the existence of ADUs regardless of what city zoning allows. We coordinate directly with your HOA to get early clarity and avoid surprises.

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

Permitting timelines vary based on the complexity of your project. Here’s a general range:

• Preliminary design & zoning analysis: 2–3 weeks
• Architectural plans and submission: 4–6 weeks
• City review and approval: 4–12 weeks

We help streamline the process by submitting clean, code-compliant plans the first time.

8. Will my ADU require special inspections?

Yes. ADUs must pass multiple inspections during construction, including foundation, framing, electrical, plumbing, insulation, and final walkthroughs. If it’s a basement conversion, we also check for egress and radon mitigation. These inspections are coordinated by our project managers.

9. Are there different rules for ADUs in surrounding cities?

Yes. While Denver has its own zoning code, cities like Lakewood, Aurora, Arvada, and Littleton all have different ADU rules. Some are more ADU-friendly than others. Before starting any design or budgeting, we do a full code review for your city and county.

10. Can I rent out my ADU once it’s built?

Yes—but with limitations. Denver requires the property owner to live on site in either the main home or the ADU. If you’re planning to use it for short-term rental (like Airbnb), you’ll need an additional license and compliance with city rules. Long-term renting (30+ days) is generally allowed.

🚧 Build with Confidence, Not Confusion

Permitting and zoning are the most intimidating parts of the ADU journey for most homeowners—but that’s where Denver Dream Builders comes in. We handle the paperwork, code interpretation, and agency coordination so you don’t have to.

Ready to get your project started?

📞 Call us today or book a consultation online to find out if your lot is eligible and what’s possible.