Yes: Denver allows one ADU with every single-unit home in every zone district that permits a house, citywide since CB24-1303 took effect Dec 16, 2024 (Denver Zoning Code Sec. 11.8.2). In single-unit (SU) districts the ADU's floor area is capped at 864 sq ft on lots of 7,000 sq ft or less and 1,000 sq ft on larger lots; a detached unit sits in the rear of the lot, up to 2 stories/24 ft in Urban and Urban Edge districts (1 story/17 ft or a 2-story option with a deeper rear setback in suburban S-SU districts). No parking is required. In SU districts an owner must live in the house when the permit is applied for, but not afterwards. Approval is administrative: zoning, building and sewer permits filed together by a licensed contractor; the building permit runs about $1,300 at a $200,000 valuation plus plan review, and Denver Water charges a $2,170 ADU system development charge.
Zoning & Size Requirements [1][2][3][4][5][6][7][8]
Yes — Denver allows ADUs. A detached ADU can typically be up to 864 sq ft under current Colorado and Denver zoning rules.
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| Allowed Zones | 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. |
| Max Size (Detached) | SU districts: ADU gross floor area 864 sq ft on lots of 7,000 sq ft or less, 1,000 sq ft on larger lots (DZC 11.8.2.1.B.2); the detached ADU building footprint is capped at the same 864/1,000 sq ft (e.g., DZC 5.3.4.5.A). Other districts: 1,000 sq ft footprint per unit, GFA not separately capped. |
| Max Size (Attached) | SU districts: 864 sq ft (lot 7,000 sq ft or less) or 1,000 sq ft (lot over 7,000 sq ft) gross floor area. All other districts: 75% of the primary dwelling's GFA or 864 sq ft, whichever is greater (DZC 11.8.2.1.B.2). |
| Max Size (JADU) | 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). |
| Max Height | Detached ADU: 2 stories / 24 ft in Urban (U-) districts; in E-SU and S-SU districts either 1 story / 17 ft (Option A) or 2 stories / 24 ft (Option B, which requires the deeper Option B rear setback). Bulk plane starts 10 ft (12 ft on lots 40 ft wide or less in U-/E-) above the side lot line and rises at 45 degrees (DZC 3.3.4.5.A, 4.3.4.5.A, 5.3.4.5.A). |
| Max Units | 1 ADU per primary dwelling unit (DZC 11.8.2.1.A.1). Mobile homes, RVs, trailers and tiny homes on wheels cannot be used as ADUs; the ADU must have its own address. |
Setback Requirements [1][2][3][4][5][6][7][8]
Denver requires a rear setback of about 5 ft for a detached ADU, and parking requirements vary by unit size or location. Owner-occupancy is set by local rules (confirm with the city).
| Rear Setback | U- districts: 5 ft, or 0 ft where an alley abuts the rear line and no garage door faces it. E-SU: 5 ft where an alley or street abuts the rear; otherwise 5 ft (1-story) or 12 ft (2-story). S-SU: 10 ft (1-story) or 20 ft (2-story). The detached ADU must sit in the rear 35% of lot depth (U-, E-) or rear 50% (S-) (DADU building form tables). |
| Side Setback | U- and E- districts: 3 ft on lots 40 ft wide or less, 5 ft on wider lots (side street the same). S-SU: 3 ft (lots 25 ft or narrower), 5 ft (25-62 ft wide), 7.5 ft (62 ft or wider). State law bars ADU side setbacks larger than the house's (C.R.S. 29-35-102(18)). |
| Front Setback | Not applicable to a detached ADU, which must be behind the house in the rear 35% (U-, E-) or rear 50% (S-) of the zone lot depth; the zoning code sets no minimum separation from the house (building-code fire separation applies). An attached ADU follows the house's primary-street setback. |
| Parking Required | 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). |
| 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). |
| Min Lot Size | No separate minimum lot size for an ADU; CB24-1303 deleted the 16 ADU-only '-1' districts. The only lot-size step is the floor-area/footprint cap: 864 sq ft on lots of 7,000 sq ft or less, 1,000 sq ft above that. |
Permit Process & Fees [9][10][11][12][13][14]
An ADU permit in Denver goes through a standard permit review. Review time: 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). Permit fees: 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).
| 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. |
| Review Timeline | 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). |
| Permit Fees | 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). |
| Impact Fees | Denver has no development impact fee, and ADUs are an exception to the affordable-housing linkage fee (DRMC 27-154; documented at building permit). Denver Water ADU SDC $2,170 inside Denver; a sanitary connection fee applies only if the ADU gets its own water service instead of sharing the house's. |
| 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. |
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Construction Costs [15][16][17]
Building an ADU in Denver typically costs $200,000-$450,000 ($250-$500 per sq ft); a garage conversion runs $80,000-$150,000.
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| Average Build Cost | $200,000-$450,000 |
| Cost per Sq Ft | $250-$500 |
| Garage Conversion | $80,000-$150,000 |
| Prefab ADU (Installed) | $175,000-$425,000 |
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 [18][19]
A 2-bedroom ADU in Denver rents for around $2,000-$2,500/mo, an estimated 5-8% gross rental yield on build cost.
| Avg Rent (1 Bedroom) | $1,650-$2,000/mo |
| Avg Rent (2 Bedroom) | $2,000-$2,500/mo |
| Short-Term Rental | Yes, with a Denver STR licence: the host's primary residence must be on the same lot; an ADU accessory to a single-unit home may be the STR, but not if the host lives in the ADU (DZC 11.8.10.1.C, F) |
| Est. Annual ROI | 5-8% gross rental yield on build cost |
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Recent Law Changes
What's Changed Recently
- Sept 20, 2026 re-verification against DZC Articles 3, 4, 5 and 11 (amended through May 7, 2026): max height corrected to 2 stories/24 ft (1 story/17 ft Option A in S-SU and E-SU); owner-occupancy corrected (still required at permit application in SU districts, DZC 11.8.2.2.B); parking attributed to Denver's own Aug 11, 2025 amendment; unsupported pre-approved-plan, 15 ft separation and 650 sq ft claims removed
- Aug 17, 2026: DOTI sewer use & drainage permit (SUDP) residential requirements revised - $425 application fee, $150 connection inspection; shared water service avoids a sanitary connection fee for the ADU
- July 1, 2026: Denver Water's ADU system development charge rose from $2,055 to $2,170 (schedule now adjusted annually by PPI)
- Aug 11, 2025: Modernizing Parking Requirements text amendment removed minimum vehicle parking citywide, including for ADUs
- Dec 16, 2024: CB24-1303 allows ADUs in every residential district, deletes the ADU-only '-1' districts, and limits owner-occupancy to the time of permit application (implements HB 24-1152)
Tips for Building an ADU in Denver
- Cost basis: two Denver builders' 2026 guides - $150,000-$350,000+ for 400-1,000 sq ft and detached $250,000-$500,000+ (typical $350,000-$450,000 for 900 sq ft); prefab all-in $175,000 (245 sq ft) to $425,000 (735 sq ft) from a 2026 modular guide; builders quote 8-12 months design to move-in
- Find your zone district first: SU districts (U-SU-, E-SU-, S-SU-) carry the 864/1,000 sq ft GFA cap and the permit-time owner-occupancy rule; TU, RH and mixed-use districts do not, though a detached unit's footprint is still capped at 1,000 sq ft
- Suburban and Urban Edge single-unit lots choose Option A (1 story, 17 ft) or Option B (2 stories, 24 ft) and must take the whole column: Option B means a 20 ft rear setback in S-SU and 12 ft in E-SU without an alley
- Worked fee example at a $200,000 valuation: building permit $1,330 + plan review $665 + zoning permit $250 + SUDP $575 + Denver Water SDC $2,170 = about $5,000 before trade permits, address fee and the URCO deposit
- Gather owner-occupancy proof before applying in an SU district: two of driver's licence, vehicle registration, voter registration, tax documents or a utility bill showing the house as your primary residence
- Keep water, sewer and electric on shared systems where feasible: a separate water tap triggers a Denver Water licence and can add a sanitary connection fee, and a shared-sewer covenant is recorded for ADUs
- Short-term renting the ADU works only if you live in the main house; renting the house short-term while living in the ADU is prohibited, and all STRs need a Denver licence
ADU Builders in Denver
Looking for an ADU builder in Denver? ADU projects need a contractor experienced with local zoning, the permit process, and utility connections — not every general contractor has built one. We match Denver homeowners with experienced local ADU contractors who provide free, no-obligation quotes. Getting at least three bids typically saves 20-40% on the same scope.
Sources & References
All data on this page is sourced from official government records and verified market data. View our full methodology.
- Denver Zoning Code Article 11, Sec. 11.8.2 Accessory Dwelling Unit (use limitations, size table, owner occupancy) and 11.8.10 Short-term Rental - amended through May 7, 2026 Municipal Code — Accessed 2026-09-20
- Denver Zoning Code Article 5 (Urban), Sec. 5.3.4.5.A Detached Accessory Dwelling Unit building form Municipal Code — Accessed 2026-09-20
- Denver Zoning Code Article 4 (Urban Edge), Sec. 4.3.4.5.A Detached Accessory Dwelling Unit building form Municipal Code — Accessed 2026-09-20
- Denver Zoning Code Article 3 (Suburban), Sec. 3.3.4.5.A Detached Accessory Dwelling Unit building form Municipal Code — Accessed 2026-09-20
- Citywide ADUs text amendment (CB24-1303, eff. Dec 16, 2024) - project page Planning Department — Accessed 2026-09-20
- Citywide ADUs Text Amendment Summary (owner occupancy at permit application, deletion of '-1' districts) Planning Department — Accessed 2026-09-20
- Zoning Administrative Policy 2025-2: parking review after June 30, 2025 (Modernizing Parking Requirements amendment eff. Aug 11, 2025) Planning Department — Accessed 2026-09-20
- Colorado HB 24-1152, signed act - C.R.S. 29-35-102(18), 29-35-103 (ADU requirements for subject jurisdictions) Government Data — Accessed 2026-09-20
- Permitting an Accessory Dwelling Unit (ADU) - Denver CPD Planning Department — Accessed 2026-09-20
- Development Fees - Denver CPD (building permit and zoning permit fee tables) Planning Department — Accessed 2026-09-20
- EHA Ordinance and Affordable Housing (Linkage) Fee - exceptions incl. Accessory Dwelling Unit Planning Department — Accessed 2026-09-20
- DOTI Sewer Use & Drainage Permit (SUDP) Residential Permit Requirements, eff. Aug 17, 2026 (fee schedule p. 3) Planning Department — Accessed 2026-09-20
- Denver Water System Development Charges - fee schedule effective July 1, 2026 (Accessory Dwelling Units $2,170) Government Data — Accessed 2026-09-20
- Average Plan Review Times - Denver CPD (live dashboard) Planning Department — Accessed 2026-09-20
- Denver Home Additions - How Much Does It Cost to Build an ADU in Denver in 2026? industry — Accessed 2026-09-20
- Denver Dream Builders - How Much Does an ADU Cost to Build in Denver? (Apr 7, 2026) industry — Accessed 2026-09-20
- Olerra - ADU Construction Cost in Denver: 2026 Homeowner's Guide (modular all-in pricing) industry — Accessed 2026-09-20
- HUD FY2026 Fair Market Rents - Denver-Aurora-Centennial, CO MSA (1BR $1,754, 2BR $2,089) Government Data — Accessed 2026-09-20
- Short-Term Rentals - Denver Business Licensing (primary-residence licence requirement) Planning Department — Accessed 2026-09-20
- Denver ADU Interactive Map Planning Department — Accessed 2026-09-20
- Colorado ADU Legislation (HB 24-1152) - bill page Government Data — Accessed 2026-09-20
- Denver Zoning Code - index page (code amended through May 7, 2026; policies and interpretations) Municipal Code — Accessed 2026-09-20
Frequently Asked Questions
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