The basis of your replacement property is not what you paid for it. That trips up a lot of real estate investors who expect to start fresh with a new cost basis after a 1031 exchange. Instead, you carry over the adjusted basis from the relinquished property and add any additional cash (boot) you put into the deal.

Here’s a simple example. You bought a rental property years ago for $300,000 and have taken $80,000 in depreciation. Your adjusted basis is $220,000. You sell it for $400,000 and use a 1031 exchange to buy a replacement property for $500,000, putting in $100,000 of additional cash to cover the difference. Your new basis is $220,000 (old adjusted basis) plus $100,000 (boot paid), which equals $320,000. Not $500,000.

Depreciation on the replacement property splits into two pieces. The first piece is the carryover depreciation from the relinquished property. You continue depreciating the $220,000 of carried-over basis on the same schedule and method the old property was using. If you had 18 years left on the original 27.5-year residential schedule, you keep depreciating that portion over those remaining 18 years.

The second piece is a brand new depreciation schedule on the additional $100,000 of basis (the boot you paid). This starts a fresh 27.5-year schedule for residential rental property beginning in the month you acquire the replacement property. So your annual depreciation deduction after the exchange comes from two separate calculations running simultaneously.

Documentation is everything with 1031 exchanges. Keep the closing statements from both the sale and the purchase, the exchange agreement from your Qualified Intermediary, and a detailed worksheet showing how you calculated the new basis. A Qualified Intermediary is required by law to facilitate the exchange. You cannot touch the proceeds yourself between selling one property and buying the next.

If you received any boot (cash back or debt relief that wasn’t offset), that portion is taxable and reduces your carryover basis. The calculations get more involved with partial exchanges, multiple replacement properties, or exchanges involving both residential and commercial property. These situations benefit from professional help.

In your books, set up the replacement property with the correct carryover basis from day one. Don’t enter it at the purchase price. Recording it at $500,000 when your actual depreciable basis is $320,000 means your depreciation deductions will be wrong, your balance sheet will be overstated, and your tax return will need corrections. Getting this right at the time of the exchange saves hours of cleanup later.

Track the two depreciation layers as separate line items or use your tax software’s asset module to handle them. QuickBooks doesn’t natively handle complex depreciation well, so many investors track fixed assets and depreciation in their tax software or a separate schedule and then post the annual depreciation entry into QuickBooks. Either way, the math needs to be documented clearly enough that anyone reviewing your books can trace back to the original exchange.

If you’re building a portfolio through multiple 1031 exchanges over the years, each successive exchange carries forward the accumulated deferred gain. The tracking compounds in complexity with every exchange. Maintaining clean records from the start with construction job costing in Phoenix or investment property accounting is far easier than reconstructing exchange histories years later when basis questions come up during a sale or audit.