A garage conversion is usually the lowest-cost path to an ADU in Denver — $80,000-$150,000, versus $200,000-$450,000 for a new detached build — because the shell already exists.
Garage Conversion Cost in Denver
Converting an existing garage in Denver runs $80,000-$150,000. That's well under the $200,000-$450,000 typical cost of a ground-up detached ADU, because you're reusing the foundation, walls, and roof. The biggest variables are whether the slab and framing are sound, what utility/electrical upgrades are needed, and your finish level. Permit fees add Building permit is valuation-based: $770 + $5.60 per $1,000 over $100,000 (about $1,330 at $200,000) plus a 50% plan-review fee; zoning permit $150 + $0.50 per $1,000; SUDP $425 application + $150 inspection; Denver Water ADU system development charge $2,170 (from Jul 1, 2026).. A converted unit rents for about $1,650-$2,000/mo (1BR) in Denver.
The Denver Garage Conversion Permit Process
A garage-to-ADU conversion in Denver needs building permits even if the exterior is unchanged. Approval process: Administrative, no hearing: zoning, building and sewer use & drainage (SUDP) permits are filed together in Denver e-permits (scope 'New Accessory Dwelling Unit') for simultaneous review. A licensed contractor must apply; homeowners cannot pull ADU permits. Landmark or historic-district properties need a certificate of appropriateness first. The review timeline is Not published as a fixed figure: Denver's Average Plan Review Times dashboard (updated daily) shows current 'Major Residential' review times. Trade permits for new construction need the issued residential construction permit first (since May 22, 2025)., with plan check: Zoning, building and SUDP reviews run concurrently when all required documents are uploaded with the initial application; a property survey is needed if building within 3 ft of a lot line. New construction over 500 sq ft also needs an approved URCO waste-diversion plan and refundable deposit before the permit issues.. Pre-approved plans: None: Denver CPD offers no pre-approved ADU plan set (only a sample site plan and elevations, checked Sept 2026). Any plan or fee help under Colorado's HB 24-1152 grant program would be announced by the city, not by this page..
- Confirm eligibility — ADUs are allowed in All zone districts that allow a single-unit dwelling, citywide since CB24-1303 (eff. Dec 16, 2024), including Former Chapter 59 districts and PUDs that permit single-unit homes (DZC 11.8.2.3 bars ADU prohibitions in PUDs). ADUs accessory to duplex, row-house or multi-unit buildings must be detached (DZC 11.8.2.1.A.2). Check your district on Denver's ADU map..
- Prepare conversion plans — layout, egress windows, insulation, ventilation, smoke/CO detectors, plus a kitchen and bathroom.
- Submit for plan check — Zoning, building and SUDP reviews run concurrently when all required documents are uploaded with the initial application; a property survey is needed if building within 3 ft of a lot line. New construction over 500 sq ft also needs an approved URCO waste-diversion plan and refundable deposit before the permit issues..
- Pull permits and build — fees run Building permit is valuation-based: $770 + $5.60 per $1,000 over $100,000 (about $1,330 at $200,000) plus a 50% plan-review fee; zoning permit $150 + $0.50 per $1,000; SUDP $425 application + $150 inspection; Denver Water ADU system development charge $2,170 (from Jul 1, 2026).; then framing, electrical, plumbing, and final inspection.
Parking Rules for a Garage Conversion
None. Denver removed all minimum vehicle parking citywide by the Modernizing Parking Requirements text amendment (adopted Aug 4, 2025, eff. Aug 11, 2025). Vehicle access must come from the alley where one exists, and the ADU may not have its own driveway except new alley access (DZC 11.8.2.1.C.1). Garage conversions sometimes trigger different parking rules than new detached ADUs, so confirm replacement-parking requirements with Denver before you start. Owner-occupancy: Only at the time of permit application, and only in single-unit (SU) districts: an owner must live in the existing house as their primary residence (shown by two of driver's licence, vehicle or voter registration, tax documents, utility bill). Waived when house and ADU are built together; no ongoing requirement (DZC 11.8.2.2.B, per CB24-1303 and C.R.S. 29-35-103(2)(b)). ADU and house must stay under one ownership (11.8.2.2.A).
The JADU Option for an Attached Garage
If your garage is attached to the house, you can convert it into a junior ADU (JADU) — capped at No JADU category in the Denver Zoning Code; a basement or in-house unit is an attached ADU under the caps above, and only one kitchen (partial or full) is allowed per ADU (DZC 11.8.2.1.C.3). and built within the existing walls. JADUs are cheaper and faster to permit than a full ADU, though they may share sanitation with the main home. A full ADU gives you more size and a separate unit; a JADU is the budget route.
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Denver Garage Conversion FAQ
How much does a garage conversion cost in Denver?
Do I need a permit to convert a garage in Denver?
Do I have to replace the parking if I convert my garage in Denver?
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Can I convert an attached garage into a JADU in Denver?
Compare your options: see the full Denver ADU rules, estimate your build with the Denver ADU cost calculator, or read the general garage conversion guide.