ADU Permits in Denver and the Denver Metro

What homeowners need to know about Colorado's ADU laws, the permit process, and how to avoid costly delays.

COLORADO HB24-1152: THE LAW THAT CHANGED EVERYTHING

In July 2024, Colorado Governor Jared Polis signed House Bill 24-1152 into law, requiring every city in the Denver metro area to allow accessory dwelling units wherever single-family homes are permitted. The deadline for full compliance is June 30, 2025.

This was a seismic shift. Before HB24-1152, most cities either banned ADUs entirely or restricted them to specific zones. Now, if you own a single-family home anywhere in the Denver metro, you almost certainly have the right to build an ADU on your property.

Separately, Denver City Council voted in November 2024 to legalize ADUs citywide — making Denver one of the most ADU-friendly cities in Colorado even before the state deadline.

THE ADU PERMIT PROCESS: STEP BY STEP

Pre-Application Zoning Check

1–2 weeks

Before anything else, we confirm your lot meets all setback, lot coverage, and height requirements for an ADU under your city's current zoning code. We identify any potential issues early — before you invest in plans or design.

Design and Engineering Documents

2–4 weeks

We prepare complete architectural drawings, structural engineering plans, and all required technical documents. These include site plans, floor plans, elevations, structural details, energy compliance, and drainage plans.

Permit Application Submission

1 day

We submit the complete permit application package to your city's planning department — Denver CPD, or the equivalent in your city. We know what each reviewer looks for and submit complete packages to avoid unnecessary revision cycles.

City Review Period

8–14 weeks

Your city's building department reviews the plans for code compliance. Denver's CPD typically takes 8–14 weeks. Other cities vary. During this period, we respond to any reviewer comments or requests for additional information.

Permit Issued — Construction Begins

Same day

Once approved, we pull the permit and begin construction. During building, we coordinate all required inspections — foundation, framing, electrical, plumbing, mechanical, insulation, and final.

COMMON PERMIT DELAYS — AND HOW 303 AVOIDS THEM

Incomplete submission packages

We submit 100% complete applications with all required documents. No missing pages, no guesswork for reviewers.

Plans that don't meet current code

Our team stays current on Denver metro building codes. We design to code from the start — not after a rejection.

Slow response to reviewer comments

When reviewers have questions, we respond within 48 hours. Delays here can add months to the timeline.

Zoning issues discovered after design

We do a thorough zoning check before design begins. No surprises at the permit counter.

ADU PERMIT FAQS

Permit review with Denver's Community Planning and Development (CPD) typically takes 8–14 weeks. Some projects may take longer if revisions are needed. 303 Construction submits complete, code-compliant plans to minimize review cycles.

Typical requirements include: site plan, architectural drawings, structural engineering plans, energy compliance documentation, and drainage plans. Requirements vary by city. 303 Construction prepares and submits all required documents as part of our standard ADU service.

Technically yes, but we strongly recommend against it. Incomplete or non-compliant submissions cause delays that cost more than the professional fee. 303 Construction handles permits as part of every ADU project — it's included in our service, not an add-on.

Yes. Colorado's HB24-1152 requires every subject jurisdiction in the Denver metro to allow ADUs wherever single-family homes are permitted. Cities must comply by June 30, 2025. This doesn't eliminate local building codes — it means cities can no longer ban ADUs.

Let Us Handle Your ADU Permits

Permits are included in every 303 Construction ADU project. We handle the paperwork so you don't have to.

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