Buying a duplex to live in: owner-occupant landlord tips
If you live in one unit of a duplex and rent the other, you are both a homeowner and a landlord. Tell your lender and insurer the plan, set clear boundaries with the tenant, keep separate records for the rented side, and split shared costs by a reasonable method such as square footage. The IRS calls this a common situation and says whole property costs must be divided.
Before you buy
Loans for homes you live in and loans for investment properties follow different rules, and a duplex can fall under either. Ask your lender, in writing, how they treat a duplex where you will live in one unit and what they want to see on the second unit's rent. Ask your insurer for a policy that fits an owner living on site with a tenant next door.
Check your city for rules that apply to two unit buildings: rental registration, inspections, and whether the second unit is legal as a separate home. An unpermitted unit is a problem for the lease and the insurance.
Living next to your tenant
The hardest part is not money. It is that your tenant knows where you are. Decide ahead of time how repairs are requested (a message, not a knock on the door), when you will enter their unit and how much notice you will give, and what is shared, such as a yard, laundry or driveway.
Put all of it in the lease: quiet hours, parking, trash day, who mows, and how the utilities are split. See the notice before entering guide for the common state pattern.
Apply the same screening rules you would apply to any applicant. Fair housing law covers renting part of a building in many cases, but some small owner occupied rentals have limited exemptions that vary. Do not rely on an exemption: ask your attorney.
Splitting costs between your side and the rented side
In Publication 527 the IRS calls the duplex where you live in one unit and rent out the other a common situation. Costs for the whole property, such as mortgage interest and real estate taxes, must be divided between rental and personal use. The two most common methods are the number of rooms and square footage, and any reasonable method may be used.
Example a made-up duplex has two units of 900 and 1,100 square feet, and you rent the larger one. The rented share is 1,100 of 2,000 square feet, or 55 percent. If the year's property tax is $4,000, $2,200 is the rental part and $1,800 is personal. Depreciation applies only to the rented part.
Costs for only the rented unit, such as repainting it, belong fully to the rental. Costs for only your unit are personal. Confirm the method with your own tax preparer.
When your tenant moves out
- Keep the same move-out inspection and deposit steps you would use on any rental.
- Use dated photos from move-in so condition is clear and neutral.
- Return or account for the deposit by your state's deadline.
- Update your records so rental days and costs for the unit are separate from your own.
Living on site does not shorten the deposit clock or loosen the rules. Treat the tenant's move-out the way you would at a building you do not live in, and the paperwork will hold up if there is ever a disagreement. If you later move out of your own side and rent both units, the way you divide costs changes, so ask your tax preparer.
How DoorKeeping handles it
DoorKeeping keeps the property's books so rental income and expenses for the rented unit are tracked from the first rent, with expense accounts mapped to Schedule E lines. You can ask Claude or ChatGPT, for example, "What did the rented side cost me this quarter?" Lease signing is electronic and approvals stay with you.
Tenants pay rent to your own bank account by bank transfer, free from DoorKeeping, and DoorKeeping marks rent paid when the deposit matches.
Sources
- Publication 527, Residential Rental Property, IRS, read Oct 30, 2026
- Topic no. 414, Rental income and expenses, IRS, read Oct 30, 2026
- 42 U.S. Code 3604, Discrimination in the sale or rental of housing, Cornell Law School, read Oct 30, 2026
Questions
- Can I rent half of a duplex I live in?
- Usually yes, if the unit is legal as a separate home and your lender and insurer know. Check city rules too.
- How do I split expenses on a duplex?
- The IRS says common methods are number of rooms or square footage, and any reasonable method may be used. Ask your tax preparer.
- Does fair housing apply when I live on site?
- Often yes, with limited exemptions that vary. Do not rely on one without asking an attorney.