The Myth - A 1031 Is Tax-Free
The most common misconception about 1031 exchanges is that they are tax-free. The pitch at meetups and on podcasts: “Sell your rental, roll it into a new one, pay zero tax, repeat forever.”
Almost right. Missing the nuance that turns a 1031 from a tax-free event into a tax-deferred event, and the specific scenarios where tax is due anyway.
A 1031 defers federal capital gains tax on qualifying replacement value. It does not eliminate the tax. The tax transfers into the new property as reduced basis. The bill comes due when you eventually sell without another 1031 (or dies with you through a step-up in basis).
Inside that deferral, two things can trigger tax during the exchange:
- Boot - any value you receive that is not like-kind real property
- Depreciation recapture - a 25 percent federal tax on gain attributable to accumulated depreciation
Neither is avoided by the exchange being valid. You can execute a clean 1031 that still generates a tax bill.
What “Boot” Actually Means
Boot is IRS slang for anything of value you receive that is not like-kind replacement property. If you receive boot, it is immediately taxable even if the rest of the exchange qualifies.
Two forms:
Cash boot. Actual cash or cash equivalents you receive or retain. Sell for $500,000, use $450,000 to buy the replacement, the $50,000 you kept is cash boot.
Mortgage boot (debt relief). The amount debt drops. If Property A had a $300,000 mortgage and Property B has $200,000, debt decreased by $100,000. The IRS treats that as cash received because you are $100,000 richer in debt obligations.
Boot is taxable at capital gains rates to the extent of your gain. Realized gain $200,000, boot $50,000, then $50,000 is currently taxable and $150,000 defers.
The rule every exchange investor should memorize: boot is taxable, but depreciation recapture comes out of boot first.
Cash Boot - The Easy Version
Cash boot is simpler. You can see it in the bank statement.
Sell Property A for $500,000. Selling costs $30,000. QI holds $470,000.
Buy Property B for $420,000 plus $10,000 closing costs. You use $430,000 of QI funds. The remaining $40,000 gets returned after day 180.
That $40,000 is cash boot. Taxable.
Common scenarios: cheaper replacement, cash taken from QI for expenses, excess QI funds past day 180, seller credit structured as cash back.
Prevention: reinvest 100 percent of net proceeds. If you want a cheaper replacement, identify additional qualifying property (up to three).
Mortgage Boot - The Trap
Mortgage boot is where sophisticated investors trip. Less intuitive. Does not show up as cash.
Rule: if debt on the replacement is less than debt on the relinquished, the difference is mortgage boot.
Clean example: sell Property A for $500,000 with a $350,000 mortgage. Proceeds $120,000. Buy Property B for $500,000, put $120,000 down, finance $380,000. Debt went from $350,000 to $380,000. No mortgage boot.
Trap: same sale, but buy Property B for $420,000. Put $120,000 down, finance $300,000. Debt went from $350,000 to $300,000. That $50,000 reduction is mortgage boot. Taxable.
Rule of thumb: in the replacement, you must buy equal or greater value AND have equal or greater debt. If either drops, boot is created.
Notes: deleveraging creates mortgage boot. Paying down replacement debt with QI funds does not cleanly work (debt at close is what counts). New cash at replacement closing offsets mortgage boot (netting). Post-close refinance does not affect the calculation.
PM-managed investors with first-plus-HELOC need to sum all debt on the relinquished. If the replacement has only a first mortgage less than that sum, mortgage boot.
How to Calculate Boot - Worked Example
Relinquished (A): Sale $600,000. Selling costs $42,000. Net $558,000. Mortgage payoff $280,000. Proceeds to QI $278,000.
Replacement (B): Purchase $520,000. Closing costs $12,000. New mortgage $240,000. Cash required at close $292,000. From QI $278,000. Investor out of pocket $14,000.
Cash boot: $0 (all QI funds used, investor added cash).
Mortgage boot: $280,000 - $240,000 = $40,000 debt relief.
Netting: investor’s $14,000 out-of-pocket offsets mortgage boot.
Net mortgage boot: $40,000 - $14,000 = $26,000.
Total taxable boot: $26,000.
Gain on A: Purchase $350,000. Improvements $30,000. Accumulated depreciation $85,000. Adjusted basis $295,000. Realized gain $558,000 - $295,000 = $263,000.
The boot is taxable. But not all boot is at capital gains rates. Recapture comes first.
Depreciation Recapture - The 25 Percent Tax
When you own a rental, the IRS lets you deduct depreciation (residential over 27.5 years). A $350,000 rental held 15 years has probably produced $85,000 to $100,000 of deductions. Example uses $85,000.
Those deductions were worth real money. At 24 percent marginal, $85,000 saved roughly $20,000 of tax over the years.
When you sell, the IRS wants some of that back. Gain attributable to depreciation is taxed at 25 percent federal as “unrecaptured Section 1250 gain.” Separate from and in addition to capital gains tax.
In a standard sale, recapture is immediate. On $85,000, that is $21,250 federal plus state.
In a 1031, recapture is normally deferred along with the gain, as long as you reinvest fully and have no boot. When you have boot, the IRS applies recapture to the boot first.
Back to the worked example. Of $263,000 realized gain, the first $85,000 is unrecaptured Section 1250 (recapture). The rest is capital gain.
The $26,000 of boot is less than the $85,000 recapture amount, so all $26,000 is taxed at 25 percent recapture.
Federal tax on boot: $6,500. Plus state and NIIT.
If boot had been $120,000, the first $85,000 at 25 percent recapture and the remaining $35,000 at 15 or 20 percent capital gains.
Many investors assume boot is taxed at 15 percent capital gains. Actually, the first chunk is at 25 percent recapture.
Order of Operations
Tax applies in this order to recognized gain:
- Unrecaptured Section 1250 (recapture) at 25 percent federal
- Long-term capital gain at 15 or 20 percent federal
- NIIT at 3.8 percent if AGI exceeds threshold
Three scenarios:
A: Zero boot. All $263,000 deferred. Replacement basis bakes in both gain and recapture.
B: $26,000 boot, less than recapture amount. All $26,000 at 25 percent = $6,500. Remaining $237,000 deferred.
C: $120,000 boot, exceeds recapture. First $85,000 at 25 percent = $21,250. Remaining $35,000 at 15 percent = $5,250. Total $26,500. Remaining $143,000 deferred.
In C, the investor thought they were doing a 1031 to defer tax. They deferred a lot, but they triggered $26,500 immediately on the boot. On a planned bill of zero, that is a surprise.
Partial 1031 - When Taking Boot Is Intentional
Not every boot outcome is a mistake.
- Need cash. Roll $200,000 into a $400,000 replacement, keep $78,000. Pay tax on $78,000, get the cash.
- Deleverage. Sold a heavily mortgaged property, want less debt. Pay tax on the debt reduction to get out from under.
- Right-size. Sold an $800,000 property, best replacement is $550,000. Take boot rather than buy something you do not want.
If full sale tax would have been $60,000 and partial 1031 tax is $15,000, you saved $45,000. Partial is not failure. It is a calibrated choice. PM-managed investors rebalancing across markets often go this route.
How to Structure the Replacement to Eliminate Boot
Zero boot rules:
- Replacement price equal or greater than relinquished sale price (net of selling costs)
- Replacement debt equal or greater than relinquished debt
- Reinvest all cash proceeds
Common mistakes: forgetting to subtract selling costs; accidental deleveraging (if initial replacement debt is less than relinquished, mortgage boot at close); identifying multiple properties and closing on fewer; forgetting that personal cash at close offsets mortgage boot.
Practical path: calculate net sale price, calculate total debt payoff, target replacement at or above net sale price, target debt at or above relinquished debt (add personal cash if loan qualifies smaller), use 100 percent of QI funds.
What Your CPA Needs
Deliver these in one package when preparing Form 8824.
Relinquished property: settlement statement, original purchase closing, capital improvements, depreciation schedule through sale date, prior 1031 documentation if acquired via exchange.
Replacement property: settlement statement, loan documents, any out-of-pocket cash brought to close.
Exchange documentation: QI Exchange Agreement, Assignment of Rights, day-45 letter, QI final accounting, amendments.
Bonus: a one-page summary so the CPA does not have to reconstruct the narrative.
Form 8824 calculates realized gain, recognized gain (taxable), deferred gain (rolled into replacement basis), and adjusted basis of the new property.
If you run DoorVault or similar, pull cost basis, depreciation, and improvements directly from the property record. Difference between a 2-hour CPA engagement and a 10-hour one.
The point of a 1031 is to defer tax. Understanding which portion defers versus which is immediately taxable is the difference between a clean deferral and an expensive surprise. Boot is not a disaster when it is planned. It is a disaster when it is not.
Related 1031 resources
- Complete 1031 guide: doorvault.app/pillar/1031-exchange
- How to choose a qualified intermediary: blog.doorvault.app/how-to-choose-1031-qualified-intermediary
- Delaware Statutory Trusts for passive 1031: blog.doorvault.app/1031-exchange-delaware-statutory-trust
- 1031 glossary: doorvault.app/glossary/1031-exchange
- 45/180 day timer: doorvault.app/tools/1031-exchange-timer
DoorVault helps PM-managed investors verify owner statements, track portfolio performance, and prepare taxes with AI-powered intelligence. DoorVault tracks cost basis, capital improvements, and accumulated depreciation per property so when you model a 1031 exchange your boot and recapture numbers are calculated from actual data, not estimates from memory. Start free at doorvault.app.
