How to House Hack in Denver With an ADU

I live in Wash Park with my wife Meghan and our daughter Olive. Behind our house is a detached ADU, and the rent from it cuts our mortgage about in half. That one unit changed how we think about our home.

I bought my first house hack in 2015, a duplex in Milwaukee. Today I own 11 rental doors across two states, and I help Denver buyers and investors do the same thing. If you want to own in Denver without carrying the whole payment yourself, an ADU is one of the best tools you have right now.

What an ADU house hack is

An accessory dwelling unit, or ADU, is a second, smaller home on the same lot as a main house. It can be a carriage house over a garage, a backyard cottage, or a unit attached to the main home. A house hack is simple: you live on the property and rent out part of it. With an ADU, you live in one home and rent the other.

The big advantage over a duplex is privacy. Your tenant has their own door, their own kitchen, and their own space.

Why Denver is a good place to do it now

The rules got a lot friendlier. In late 2024 Denver passed its Citywide ADUs measure, which allows ADUs in all residential areas of the city. The city says that opened about 70 percent of Denver's land to ADUs, up from 36 percent before. Colorado's House Bill 24-1152 also requires cities like Denver to allow ADUs wherever single family homes are allowed.

Two rules to know before you shop:

• Owner occupancy. In single unit (SU) zone districts, at least one owner has to live on the property as a primary residence when the ADU permit is applied for. If you are house hacking, you live there anyway.
• Size limits. In SU zones, an ADU can be up to 864 square feet on lots of 7,000 square feet or less and up to 1,000 square feet on larger lots. Other zone districts have their own limits.

Always check the specific address. Zoning, lot size, utilities, and the existing structure decide what you can build or legally rent.

Two ways to do it

Buy a house that already has a legal ADU. This is the fastest path. You move in, rent the ADU, and the income starts right away. Ask for the permit history and the certificate of occupancy so you know the unit is legal, not just a finished garage.

Buy a house you can add an ADU to. This takes longer and costs more up front, but it can create the most value. You need the right lot, a realistic build budget, and a plan to pay for construction. Get a bid and talk to the city before you count on the rent.

Run the real numbers

Here is how I look at every ADU deal:

• Use real rent comps. Look at what similar ADUs and small units nearby actually rented for in the last few months, not what a listing hopes for.
• Budget the full payment. Mortgage, taxes, insurance, utilities you cover, and mortgage insurance if your loan has it.
• Plan for vacancy and repairs. A small unit still has a water heater, a roof, and appliances. Set money aside every month.
• Keep a cash cushion. Tenants move out and things break. You want to handle a surprise without stress.

The goal is not to live for free. The goal is to cut your housing cost a lot, build equity, and learn to be a landlord with a safety net under you.

How I made my own deal work

When we bought in Wash Park, I used my agent commission and some creative negotiating, and I was paid about $30,000 to buy the house. Then the ADU rent took a big bite out of the monthly payment. You do not need to be an agent to win on an ADU house hack, but you do need to negotiate hard, check the rules, and buy on real numbers.

FAQ

Can I build an ADU anywhere in Denver? Denver allows ADUs in all residential zone districts, but your lot and zoning set the details, like size and placement. Check the specific address before you buy.

Do I have to live on the property? In single unit zone districts, an owner has to live on the property as a primary residence when the ADU permit is applied for. Other zone districts can differ.

How big can a Denver ADU be? In SU zones, up to 864 square feet on lots of 7,000 square feet or less and up to 1,000 square feet on larger lots. Other zones have different limits.

Can I use an FHA loan for a house with an ADU? Often yes, if you will live in the main home. Loan rules on counting ADU rent change, so ask a lender what applies to you.

Can I rent my ADU on Airbnb? Denver short term rental licenses are tied to your primary residence. Check the current city rules for your address before you plan on nightly rentals.

Ready to find your ADU house hack?

I help Denver buyers and investors find properties with an ADU or the potential for one, and I will tell you honestly if the numbers work. Call or text me at (719) 350-6436 or email chad@thefiteam.com. You can also see my reviews and background on my agent page.

Want to meet other people doing this? Join The Denver Real Estate Meetup, a free monthly gathering for Denver investors. Our next one is the holiday party on Wednesday, Dec. 9, at Jackson's LODO.

This post is general information, not legal, tax, or lending advice. Rules change, so verify the details for your property with the City and County of Denver and your lender.