1031 Exchange Into a Duplex or Fourplex You Will Partly Live In (House Hack)

Only the rented units are replacement property, so the building is two purchases in one

Section 1031(a)(1) requires the replacement to be held for productive use in a business or for investment. The units you rent meet that test; the unit you live in does not, any more than a house would. You buy one deed, but for tax purposes you acquire a rental property and a residence.

Split the price on a reasonable basis. IRS Publication 527 describes the duplex where you live in one unit and rent the other and says expenses for the whole property are divided between rental and personal use by any reasonable method, most commonly rooms or square footage. Rev. Proc. 2005-14 cites square footage as an appropriate way to allocate basis and amount realized between home and business portions.

Exchange money that pays for your unit buys property that is not like-kind. Under section 1031(b) gain is recognized up to the cash and the fair market value of other property you receive, so the share of exchange funds that lands on your unit is taxable to that extent. Pay for your unit with your own cash and your share of the loan.

The exchange math applies to the rental portion alone

For full deferral, the rental units' share of the price has to be at least the price of the property you sold, and the debt and cash on that portion have to replace the debt paid off at your sale. The personal unit adds nothing to either test.

Hypothetical: you sell a rental for $600,000. You buy a fourplex for $1,000,000 with four equal units and live in one, so the rental portion is $750,000 and the personal portion is $250,000. The $750,000 rental share exceeds the $600,000 you sold, so the value test is met; if any of your exchange proceeds pay for the $250,000 personal share, that amount is taxable boot to the extent of your gain. Run your own numbers with your CPA.

How a single mortgage is divided between the two portions affects the debt test and the interest deduction, so have your CPA document the allocation at closing rather than at tax time. The sale-side duplex and fourplex page covers the reverse case of selling a building you partly occupied.

FHA and other owner-occupied loans bring occupancy rules the exchange does not

HUD Handbook 4000.1 requires at least one FHA borrower to occupy the property within 60 days of signing the security instrument and to intend to continue occupancy for at least one year, and it defines a principal residence as the home you occupy for most of the year, adding that a person may have only one principal residence at a time. If you already own a home you plan to keep living in, an FHA loan on the duplex is not available.

Three- and four-unit FHA purchases must also pass a self-sufficiency test: the monthly mortgage payment, including taxes and insurance, divided by the net self-sufficiency rental income may not exceed 100%. Net rent is the appraiser's market rent for all units, including yours, minus the greater of the appraiser's vacancy and maintenance estimate or 25%.

None of this conflicts with the exchange if the facts are true: the lender needs you in one unit and the IRS needs the others rented. The conflict comes from plans that change, such as moving into a second unit or out of the building in the first year, which can breach a loan certification and weaken the investment intent for the units you exchanged into.

Basis, depreciation and expenses follow the same split

The basis carried over from the rental you sold attaches to the rental units, and under Reg. section 1.168(i)-6 it keeps depreciating on the old schedule; any new money in the rental portion starts a new 27.5-year schedule. Your own unit is not depreciated, and its basis is what you paid for it.

Mortgage interest and property taxes are divided between Schedule E for the rental units and Schedule A for your unit, and expenses for one portion only, such as painting a rented unit, go entirely to that portion, as Publication 527 explains. Keep the floor-area figures and the allocation memo with the closing statement; you will need them every year and again at sale.

Moving units or moving out later changes the tax picture

If you later move into one of the units you acquired in the exchange, section 121(d)(10) denies the home-sale exclusion on property acquired in a 1031 exchange that is sold within five years of the acquisition, and nonqualified use can reduce the exclusion after that. The moving into a replacement property page walks through the timeline.

If you sell the whole building years later, the portion you live in can qualify for the home-sale exclusion and the rented portion can be exchanged again, with the price split on the same method you used at purchase. The home-sale exclusion versus 1031 guide covers that combined sale.

Before day 45: what to have settled before you identify

Get unit floor areas from the appraisal or a measured plan, signed leases or market-rent estimates for each rental unit, and your lender's written confirmation of the occupancy and self-sufficiency requirements. Confirm with your intermediary how the closing statement will show exchange funds applied only to the rental portion.

Identify the whole property; the allocation happens at closing, not on the identification. Reg. section 1.1031(k)-1(c)(4) allows three properties, so name a second small multifamily building or an all-rental backup in case the owner-occupied loan does not close in time. If living on site turns out not to be the goal, a traditional DST takes the whole exchange with no occupancy rules at all.