House hacking a duplex: how to be your neighbor's landlord

House hacking a duplex sounds simple on paper: live in one side, rent the other, and let the rent help with the mortgage. The part nobody puts in the spreadsheet is that your tenant is now your neighbor, through a shared wall. Here is how to run an owner-occupied duplex so the rent arrives on time and the relationship stays easy, from the loan rules to the shared water bill to tax time.

You are in good company

Small buildings carry a big share of American rentals. According to the Census Bureau and HUD's 2021 Rental Housing Finance Survey, about 46% of US rental units are in properties with one to four units, about 70% of those small properties are owned by individuals, and only about 22% are professionally managed. Most duplex owners are doing it themselves, with no manager in between. That makes your own systems the whole show.

Before you buy: the owner-occupancy fine print

Many owners buy a duplex with an FHA, VA, or conventional loan that is meant for a home the borrower will live in. Loans like these come with owner-occupancy requirements: you agree to move in and live there, usually within a set time and for a set period. The details differ by loan program and lender, and they can change, so ask your lender exactly what you are agreeing to and get it in writing. Do not assume you can move out and rent both sides right away. This is general information, not legal or lending advice.

Being your neighbor's landlord

The awkward moments in a house hack come from mixing two relationships. As a neighbor you borrow ladders and wave from the porch. As a landlord you collect money, enforce rules, and make repairs. The trick is to keep each one in its own lane.

• Rent is never a hallway conversation. It is an invoice with a due date, paid online, with a receipt.
• Repairs are requests, not favors. They come in writing, and you answer in writing.
• Rules live in the lease. If something matters to you, like noise after 10 pm or who uses the driveway, write it down before move-in.

Keep payments formal from the first month

The easiest habit to fall into is the informal one: cash handed over at the door, a payment app transfer "sometime this week," a check slid under the door. It feels friendly until a payment goes missing and you have no record of what was paid when. It is common, too. In a January 2025 survey of 415 rental owners by Baselane and Centiment (a vendor survey where owners could give more than one answer), 56% said they collect rent by check, 53% by cash, and 49% through payment apps.

A more formal setup costs you a few minutes once:

1. Add the duplex as one property. Units are optional in RentMerchant, but a duplex is a natural fit for one property with two units: yours and the rental.
2. Add your tenant to their unit, and if two people share the lease, put both on the invoice so either can pay.
3. Set up recurring monthly rent on the day of the month in your lease.
4. Let invoices go out automatically, with email reminders before and after the due date.
5. Add a late fee if your lease has one, within what your state allows. See our late fee laws by state guide.

Your tenant pays online by bank transfer or card, and can turn on autopay with a card. If they still hand you a check, record it against the invoice so the ledger stays complete. Nothing about the money depends on remembering a conversation over the fence.

Shared utilities without a monthly argument

Many duplexes share at least one meter, often water. Splitting the actual bill every month invites debates about long showers and houseguests. Most owners pick one of three setups:

• Include it in the rent. Simplest for both sides; price the rent with typical usage in mind.
• Charge a flat monthly amount. Write it into the lease and put it on the invoice as part of the monthly total, for example "Rent $1,350 + water (flat) $60". Revisit it once a year against your real bills.
• Separate meters. More expensive to set up, but the tenant pays the utility company directly and you are out of it.

Two honest notes. First, RentMerchant does not read meters or split utility bills; a flat amount on the invoice is the way to handle it. Second, some states regulate how landlords can bill tenants for utilities, so check your state's rules before you charge for them.

Boundaries with a shared wall

Duplexes come with shared things: a yard, a driveway, a basement, laundry, sometimes a porch. Each one is a future disagreement unless you settle it up front.

• Name the shared spaces in the lease, and who may use them for what.
• Agree on noise and guests in plain language. Shared walls carry sound both ways, so hold yourself to the same rules.
• Give proper notice before entering their unit, following your state's rules, even if you only live a wall away.
• Keep your own unit out of their business. Living next door does not mean supervising.

Maintenance requests in writing

When your tenant can knock on your door, every leak arrives as a knock. That works until you are on vacation, or the tenant says they told you about the leak weeks ago and you do not remember. Ask your tenant to submit maintenance requests through the tenant portal, and reply through messaging. You both get a dated record of what was reported, when you responded, and when it was fixed. For an emergency like a burst pipe, they should still call you; the written request can follow.

Taxes when you live on site

A house-hacked duplex is part home and part rental, and the tax treatment generally follows that split. Rental income from the other unit is generally reported on Schedule E.

• Expenses only for the rental unit, like a repair inside their side, generally count fully as rental expenses.
• Expenses only for your unit generally do not count as rental expenses.
• Shared expenses, like property tax, insurance, mortgage interest, or a new roof, are generally divided between the two sides using a reasonable method. With two equal units, that might be half and half; with unequal units, square footage is a common basis.
• Depreciation generally applies only to the rental portion.
• Selling later works differently for the part you lived in and the part you rented, including how the home sale exclusion applies.

These rules have real nuance, so confirm your own numbers with a tax professional. The practical step is to log expenses as they happen and mark which side of the building they belong to. Our Schedule E guide covers the categories.

When you move out

Many house hackers eventually move out and rent both sides. If you have kept the setup above, that is a small change: add the new tenant to your old unit, set up a second recurring invoice, and keep going. Your history, leases, and expense records are already in one place. Before you move, check your loan's owner-occupancy terms with your lender.

How RentMerchant fits

RentMerchant's Free plan covers up to three properties with unlimited units, so a duplex fits, and so does the triplex or fourplex you might buy next. You get recurring invoices, email reminders, automatic late fees, receipts, online leases, maintenance requests, messaging, and an expense tracker with a Schedule E export. Tenants pay by bank transfer or card, and by default they pay the per-payment fee so you receive the full rent; the fees page lists every amount. See the small multifamily page for how two to four unit owners use it, or, if you are renting rooms in a house you live in, the co-living page. When you are ready, create a free landlord account.