If you own rental properties and your CPA's primary job is filing your return accurately and on time, you are almost certainly overpaying your taxes. Not by a little. By tens of thousands of dollars per year. The problem is not that your CPA is incompetent. The problem is that compliance-focused tax preparation and proactive tax strategy are fundamentally different services, and most CPAs only provide the first one.
Mistake 1: No Cost Segregation Study
This is the single largest source of lost tax savings for rental property owners. Under IRC Section 168, residential rental property is depreciated over 27.5 years. But within that property are components that qualify for accelerated depreciation: appliances, cabinetry, flooring, fixtures, landscaping, and more. A cost segregation study reclassifies these into 5-year, 7-year, and 15-year MACRS categories, and under IRC Section 168(k), they qualify for 100% bonus depreciation.
A cost segregation study on a $500,000 rental can generate $150,000 to $200,000 in first-year deductions. At a 37% marginal rate, that is $55,500 to $74,000 in immediate tax savings. If your CPA has never mentioned cost segregation, they are leaving real money on the table.
Mistake 2: Missing the Form 3115 Catch-Up
If you have owned rental property for years without a cost segregation study, you are not out of luck. Under IRS Revenue Procedure 2015-13, you can file Form 3115 to claim all missed depreciation in a single year through a Section 481(a) adjustment. No amended returns needed. For an investor who purchased a $600,000 property five years ago, the catch-up deduction can exceed $100,000. Most CPAs either do not know about Form 3115 or do not want the complexity of filing it.
Mistake 3: Incorrect Passive Activity Treatment
Passive activity rules under IRC Section 469 are the most misapplied area of rental property taxation. The default rule is that rental losses can only offset passive income. But the Code provides critical exceptions.
For short-term rental operators, IRC Section 469(j)(10) and Treasury Regulation 1.469-1T(e)(3)(ii) provide that rentals with an average customer use period of seven days or less are not treated as rental activities. With material participation, STR losses become nonpassive and can offset any income type. Many CPAs still treat STR losses as passive, costing their clients thousands.
For Real Estate Professionals under IRC Section 469(c)(7), all rental activities can be treated as nonpassive. But REPS qualification requires proper documentation, time logs, and a grouping election under Treasury Regulation 1.469-9(g). If your CPA is not advising on these requirements, you are exposed to both lost deductions and audit risk.
Mistake 4: Failing to Make the Right Elections
Tax elections are choices on your return that affect how deductions are calculated. Many are available only if affirmatively claimed. The IRC Section 469(c)(7) grouping election, the de minimis safe harbor under Treasury Regulation 1.263(a)-1(f) (allowing expensing of items up to $2,500), and the IRC Section 179 election for qualifying improvements are all frequently overlooked. Each missed election is money left on the table.
Mistake 5: No Entity Structure Planning
Many CPAs file rental income on Schedule E and never discuss entity structuring. For investors with multiple properties, operating through properly structured LLCs provides asset protection, income allocation flexibility, and entity-level election capabilities. A management company structure can shift income between entities and optimize self-employment tax treatment under IRC Section 1402. Most CPAs are not equipped to integrate tax planning, legal structuring, and business strategy.
Mistake 6: No Proactive Tax Projections
A compliance CPA looks backward, preparing last year's return. A proactive advisor looks forward, modeling projected income, planned acquisitions, and estimated expenses to optimize timing of purchases, cost segregation studies, and property dispositions. If you are buying a property in October, a proactive advisor runs the cost segregation projection in September. They calculate whether bonus depreciation creates a net operating loss eligible for carryback or carryforward under IRC Section 172. They model the impact on estimated tax payments so you do not overpay the IRS.
Mistake 7: Not Tracking Basis Correctly
Your adjusted basis determines depreciation deductions, gain or loss on sale, and eligibility for various tax provisions. Basis must reflect original cost, closing costs, capital improvements, casualty losses, insurance reimbursements, and accumulated depreciation. For properties held through partnerships, basis tracking must account for contributions, distributions, and debt allocations under IRC Section 752. A proactive advisor maintains a running basis schedule for every property, updated annually.
The Cost of Inaction
Every year you file with missed cost segregation, incorrect passive activity treatment, and no forward-looking strategy, you lose money that cannot be fully recovered. AE Tax Advisors works exclusively with real estate investors and business owners who want more than compliance. We build comprehensive strategies covering cost segregation, entity structuring, passive activity planning, and multi-year projections. Call us at (631) 614-5762 or email team@aetaxadvisors.com for a free tax assessment. We will show you exactly what you are missing.