Everything homeowners need to know about building an accessory dwelling unit in Aurora - the city's current, still-limited local program, and the wider right Colorado's statewide ADU law is supposed to guarantee while Aurora finishes catching up.
Last verified: August 2026
4/10 · Behind state law, rules in transition
~800 sq ft*
Max ADU size
~20 ft*
Max height
Not required
Owner-occupancy
Limited areas*
Permit type
Aurora's own ADU rules are unusually unsettled right now: the city's adopted zoning code still only allows ADUs in a limited area, even though Colorado's statewide ADU law (HB 24-1152) has required by-right ADUs on every single-family lot since June 30, 2025. This page explains both sides of that gap. It is not legal advice - confirm current status with Aurora's Development Center before designing or applying for permits. See sources below.
Zoning & size requirements
What's currently allowed, and what's supposed to be allowed
ADU type
Max size
Max height
Notes
Detached (Aurora's current adopted program)
Roughly 800 sq ft, per the city's existing standards
Roughly 20 ft
Only permitted on Original Aurora lots served by an alley, and in the Painted Prairie master-planned community
City staff have proposed allowing internal and attached ADUs citywide as part of the pending rewrite
Allowed zoning districts
As adopted, Aurora's Unified Development Ordinance still limits ADUs to Original Aurora lots with alley access, plus the Painted Prairie neighborhood - a narrow slice of the city. Colorado's HB 24-1152 legally requires "subject jurisdictions" like Aurora to allow at least one ADU by right on every lot zoned for a single-family detached home, effective June 30, 2025, and state law generally preempts a conflicting local ordinance. In practice that means many Aurora homeowners outside the currently-approved area may already have a state-law right to build an ADU even though the city's own zoning map hasn't caught up yet. Confirm your specific situation with Aurora's Development Center before designing.
Additional standards
Setbacks, parking & other rules
Setbacks
Detached ADUs generally follow the underlying zone district's accessory-structure setbacks; confirm exact figures with Aurora's zoning code for your specific lot
Parking
Aurora's existing program has historically expected an off-street parking space for the ADU; HB 24-1152 bars most parking mandates statewide, so this is one of the standards likely to change under the pending rewrite
Units per lot
1 ADU permitted per single-family detached lot where ADUs are currently allowed
Owner-occupancy
Not required. Aurora's program has not required owner-occupancy, and HB 24-1152 bars owner-occupancy mandates statewide regardless
Building code
Must meet Aurora's adopted building code dwelling-unit standards
Approval process
Aurora's prior process involved Planning and Zoning Commission review; HB 24-1152 requires administrative-only approval statewide, with no public hearing, for compliant ADU applications
Ordinance history
How Aurora's ADU rules got here
2018Pilot ADU program launched. Aurora began allowing detached ADUs, but only on lots zoned Original Aurora with alley access. Between 2018 and mid-2026, the city permitted just nine units and saw five actually built.
2024Colorado passes HB 24-1152. The state legislature approved a statewide ADU law requiring subject jurisdictions, including Aurora, to allow at least one ADU by right on every single-family lot, with administrative-only approval and no owner-occupancy or blanket parking mandates, by June 30, 2025.
2025State deadline passes. HB 24-1152 took full effect June 30, 2025, but Aurora had not yet adopted a citywide ordinance extending ADU eligibility beyond Original Aurora and Painted Prairie.
2025State names Aurora non-compliant. In an October 2025 compliance review, the Colorado Department of Local Affairs (DOLA) listed Aurora among more than a dozen cities not yet meeting HB 24-1152's requirements, putting the city at risk of losing access to certain state housing grant funding.
2026Council directs staff to draft a fix. At a July 13, 2026 study session, City Council directed staff to prepare a citywide ADU ordinance allowing internal, attached, and detached units on all single-family lots, alongside a report that the city had fielded 262 ADU construction inquiries from property owners outside the currently eligible area since 2023. As of this writing, no new ordinance had been adopted.
Aurora is a useful reminder that a state law taking effect and a city's own zoning code catching up to it are two different things. If you're outside the historically eligible area, talk to Aurora's Development Center directly about whether your project can proceed under HB 24-1152 while the local ordinance rewrite is still pending.
Permit process
How Aurora ADU permitting currently works
1
Confirm your eligibility directly with the city
Because the local ordinance is being rewritten, don't rely solely on the zoning map - ask Aurora's Development Center whether your specific lot currently qualifies under city rules, state law, or both.
2
Check the Original Aurora / Painted Prairie boundary
If your lot is Original Aurora-zoned with alley access, or in Painted Prairie, you're inside the city's existing approved program.
3
Prepare your plan set
Site plan, floor plans, and elevations for the detached ADU, sized to the roughly 800 sq ft / 20 ft standard currently in the code.
4
Submit for zoning and building review
Applications inside the eligible area go through Aurora's standard zoning and building permit review process.
5
Plan review & permit issuance
City staff review for zoning and building code compliance before issuing the building permit.
6
Inspections
Schedule the standard framing, plumbing, electrical, and final inspections through construction.
If your lot is outside the currently eligible area, ask the Development Center how the city is currently handling HB 24-1152 requests while the citywide ordinance is still being drafted - the answer has been changing through 2026.
Budgeting
What it costs to build an ADU in Aurora
Garage conversion
Roughly $65,000-$155,000, the least expensive path since the shell already exists
Basement conversion
Roughly $95,000-$200,000, depending on existing ceiling height and utility access
New detached ADU
Roughly $140,000-$290,000 for a code-compliant, fully insulated freestanding unit
Building permit fees
Set by Aurora's standard permit fee schedule based on project valuation; confirm current figures with the city's Development Center
These are general ranges from local contractor estimates and regional reporting, not quotes - actual cost depends heavily on lot conditions, utility access, and finishes. Aurora construction costs generally track close to the broader Denver metro.
Before you apply
Tips for a smooth approval
Don't assume the zoning map is the final word. Aurora's own program is narrower than what state law requires, so a "no" from the map may not be the whole story - ask the Development Center about your rights under HB 24-1152 directly.
Check whether you're inside Original Aurora or Painted Prairie first. Those areas have a working, established process today rather than one that's still being drafted.
Watch for the citywide ordinance update. Council directed staff to draft new rules in July 2026; the final standards for size, height, and design could differ from what's in place today.
Get any parking or design expectations in writing. With standards actively changing, a written answer from Development Center staff protects you if the rules shift mid-project.
Ask about HOA restrictions separately. HB 24-1152 limits how much an HOA can restrict ADUs, but the details are worth confirming if your property is in a covenant-controlled community.
FAQ
Common questions
Why doesn't Aurora allow ADUs everywhere yet, if state law requires it?
Colorado's HB 24-1152 took full effect June 30, 2025, but adopting a matching local ordinance is a separate step that takes each city time. The Colorado Department of Local Affairs named Aurora among the cities not yet compliant in an October 2025 review, and as of mid-2026 the city was still drafting a citywide ordinance. State law preemption may still give homeowners rights beyond what the city's own map currently shows - confirm your situation directly with the city.
Do I need to live on the property to build an ADU in Aurora?
No. Aurora's existing program hasn't required owner-occupancy, and Colorado's HB 24-1152 bars owner-occupancy requirements statewide.
How many ADUs can I build on one lot?
One, in addition to the primary dwelling, on lots where ADUs are currently permitted.
Do I need extra parking for an ADU?
Aurora's existing program has generally expected an off-street parking space, but Colorado's statewide ADU law bars most local parking mandates, so this standard is likely to loosen as the city updates its ordinance.
What's the maximum size for a detached ADU in Aurora?
Roughly 800 sq ft with a roughly 20 ft height limit under the city's current adopted standards - confirm the exact figures for your zone district with the Development Center, since these are among the standards under active review.
How long does the permit process take?
For projects inside the currently eligible area, timelines follow Aurora's standard zoning and building review process. For projects outside it, timelines depend on how the city is currently handling HB 24-1152 requests, which has been evolving through 2026 - ask the Development Center for the current process.
How much does an ADU cost to build in Aurora?
Garage conversions run roughly $65,000-$155,000, basement conversions roughly $95,000-$200,000, and new detached units roughly $140,000-$290,000, based on local contractor estimates and regional reporting - not counting permit fees.
Is Aurora a "subject jurisdiction" under Colorado's ADU law?
Yes. As a city well over 1,000 residents inside the Denver metropolitan planning area, Aurora is a subject jurisdiction under HB 24-1152, meaning the law's by-right ADU requirements apply to it regardless of where the city's own ordinance rewrite currently stands.
Can I rent my ADU out on Airbnb or a short-term rental platform?
Short-term rentals are regulated separately from standard ADU permitting in Aurora. If that's the plan, confirm current short-term rental licensing requirements with the city before finalizing your design.
