Denver House Hacking Guide
ADU House Hacking in Denver
A basement suite, garage flat or backyard cottage can turn one Denver mortgage into two households. Here are the rules, the real costs and the permit path in 2026.
By Jeffrey White, Realtor® · Updated October 2026 · 720-951-6868
What counts
ADU types that work in Denver
An accessory dwelling unit is a second, smaller home on a single-family lot — and for house hackers it is the highest-control rental you can own. Three formats dominate Denver: basement apartments (fastest and cheapest where ceiling height, egress windows and a separate entrance work), garage conversions (the structure exists; utilities and insulation are the budget), and detached backyard cottages (the classic carriage house — most expensive, most private, and the format tenants pay premium rents for).
The rules, 2026
Denver ADU rules after HB24-1152
Colorado's HB24-1152 pushed cities to allow ADUs in single-family zones, and Denver now permits them broadly — but 'allowed' still means permitted, inspected and approved. Lot zoning, size, setbacks, height, lot coverage and parking rules apply property by property, and the city issues a certificate of occupancy when the unit is legal to rent. Start from the city's own guidance at denvergov.org and verify any specific lot with the city before you price a deal around an ADU that may not pencil legally.
Two traps Jeffrey sees repeatedly: buying on the assumption a non-permitted 'mother-in-law suite' can be rented as-is (lenders, insurers and the city may all disagree), and ignoring utility capacity — older Denver panels and sewer lines can add real cost to a garage conversion. Both checks belong in the inspection period, not after closing.
The numbers
What a Denver ADU costs — and returns
| Format | Common modeling range | Rent character |
|---|---|---|
| Basement apartment | Often the lowest five figures when egress + entrance exist; more with full kitchen/bath work | Slightly below garden-level rents; strong near universities and hospitals |
| Garage conversion | Mid five figures depending on utilities and insulation | Detached privacy commands near-market 1-bed rents |
| Detached backyard cottage | Commonly modeled at $100,000–$150,000+ new-build | Premium rents; also the strongest value-add at resale |
Run your own version with the house hacking calculator — and be honest about the timeline: permits and construction commonly take months, so most clients either buy a property with an existing legal ADU or house hack the main home first and build the ADU in year two. The full strategy sits in the Denver house hacking guide; where ADUs fit best, area by area, is in the neighborhood ranking.
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FAQs
Questions, answered
Are ADUs legal in Denver now?
Broadly yes. After Colorado's HB24-1152, Denver permits ADUs across most single-family areas, subject to lot-level zoning, size, setback, height and coverage rules, plus permits and a certificate of occupancy for the unit. Always verify the specific lot with the city.
How much does it cost to build an ADU in Denver?
Basement apartments are usually cheapest when egress and a separate entrance already work. Garage conversions run mid five figures depending on utilities. A new detached backyard cottage is commonly modeled at $100,000–$150,000 or more. Every figure depends on the lot and the scope — get contractor bids during diligence.
Can I rent out an existing non-permitted suite?
That is the classic Denver trap. A space the seller called a suite may not be a legal dwelling unit; renting it anyway risks city orders, insurance problems and lender issues. Jeffrey's rule: no permit trail, no rent in the underwriting.
Do I need a rental licence for a Denver ADU?
Denver's residential rental licence generally applies to rented units, including ADUs rented long-term. The full licensing picture — inspections, timelines and what officers check — is in the Denver rental licensing guide.
Is it better to buy a home with an ADU or build one?
Buying with a legal ADU costs more upfront but produces rent from month one and finances inside the purchase loan. Building later spreads the cost but adds months of permits and construction. Most of Jeffrey's clients buy the ADU when they can find it — legal Denver ADUs are scarce relative to demand.
Found a Denver home with ADU potential?
Before you price the dream, let Jeffrey verify the lot's zoning signals and pull comparable ADU rents — the two checks that decide whether the plan is real.