Owning Your Dental Office Building: Self-Rental Rules, Cost Segregation, and 1031 Exchanges

A dentist who owns the building the practice operates out of usually bought it inside the same entity that runs the clinical business, or personally, without much thought about the tax mechanics. That works, but it leaves protection, flexibility, and depreciation on the table. Holding the building in its own LLC and leasing it back to the practice at a market rent creates a legal wall between the building and the practice’s liabilities, opens a path to sell the practice without selling the real estate, and unlocks a cost segregation study a dentist rarely runs while the building sits inside the operating entity. The tradeoff is a set of rules under IRC 469 that behave differently than most dentists expect, plus related-party wrinkles under IRC 267 that show up once the landlord and the tenant are controlled by the same person. This guide covers the structure, the self-rental trap, how to price the lease, what cost segregation can do, and what happens when the dentist relocates or sells.

Why hold the dental office building in a separate entity?

Most dentists who buy their office building fund the purchase through the same PLLC or S-corp that operates the clinical practice, or buy it personally and never formalize a lease at all. Both approaches expose the building to risk it does not need to carry. If the practice entity is sued, whether for a slip-and-fall, an employment claim, or a vendor dispute, the building sits inside the same liability pool, and a judgment against the practice can reach the real estate.

Putting the building into its own LLC, typically owned by the dentist alone or jointly with a spouse, separates the two risk pools. The practice leases the space under a written lease and deducts the rent under IRC 162. The real estate LLC reports the rental income and offsets it with depreciation, property taxes, insurance, and maintenance. Creditors of the practice can reach the practice’s assets, but reaching the building requires piercing a second, separate entity.

The separate entity also solves a problem that shows up at every practice sale: a buyer wants the clinical practice and usually cannot finance the real estate at the same time. A dentist who has already separated the building can sell the clinical side, sign a new lease between the buyer and the real estate LLC, and keep collecting rent after retiring. A dentist who never separated the two either has to sell the building along with the practice, limiting the buyer pool, or unwind the structure at the moment of sale, which is more expensive than doing it years in advance. The entity decisions that come before this one are covered in the dental practice entity structure guide.

How does the self-rental rule under IRC 469 work?

This is the part of the structure that surprises most dentists the first time it applies to them. IRC 469 treats rental activity as passive by default, regardless of how much time the owner spends on it. Reg 1.469-2(f)(6), the self-rental rule, overrides that default when the property is rented to a business the taxpayer materially participates in, which describes almost every dentist renting from their own real estate LLC.

The rule cuts one way. If the real estate LLC produces net rental income (rent collected exceeds the building’s deductible expenses for the year), that income is recharacterized as non-passive and taxed as ordinary active income. If the LLC produces a net rental loss, which happens often in the early years once a cost segregation study accelerates depreciation, the loss stays passive and can only offset passive income from other sources, such as another rental property. Most dentists have no other passive income, so a self-rental loss sits suspended, carried forward year after year, until the dentist generates passive income elsewhere or disposes of the building in a fully taxable transaction under IRC 469(g).

The asymmetry exists because Congress did not want taxpayers manufacturing passive income out of a self-rental to absorb passive losses from unrelated real estate syndications or other paper-loss investments. The rule closes that door, but it closes it in a way that penalizes the dentist precisely when the rental produces a loss, which is exactly when a cost segregation study has done its job.

Can a grouping election fix the self-rental mismatch?

Yes, for most dentists this is the correct planning move. Reg 1.469-4 permits a taxpayer to elect to treat the rental activity and the practice as a single activity for passive loss purposes under IRC 469. Since the dentist materially participates in the practice, the combined activity is non-passive in its entirety, and a loss generated by the real estate LLC offsets the practice’s active income directly, the same year it arises, instead of sitting suspended. Grouping also removes the self-rental recharacterization problem at its root, since the rule only reaches a rental that is a separate activity from the business it serves.

The election has to be made in the first tax year the dentist owns both the practice and the building together, by attaching a statement identifying the grouped activities to that year’s return. Once made, it is generally irrevocable, and missing the window means defending a late grouping request on reasonable cause grounds the IRS is not required to accept. Raise this with the CPA before the first joint return is filed, not after a suspended loss has already built up. There is also a downstream consequence: if the dentist later sells the practice but keeps the building, the grouped activity splits apart, and whether suspended losses release at that point depends on whether the disposition covers the dentist’s entire interest in the grouped activity.

How do you set a fair market value lease rate?

Every advantage in this structure depends on the rent being set at fair market value, documented, and revisited periodically. Rent set above market shifts income into the entity taxed more favorably and invites the IRS to recharacterize the excess as something other than rent. Rent set below market understates the building LLC’s income and shrinks the practice’s deduction, and it undermines the property’s value if the dentist later needs to show its income history for a refinance, an appraisal, or a sale.

The standard way to establish the number is a broker opinion of value, a letter from a commercial real estate broker citing comparable lease rates for dental or medical office space of similar size and finish level. Some dentists commission a formal appraisal instead for a larger or unusually built-out space. Either way, keep the documentation with the lease file, refresh it every few years, and reflect any adjustment through a written amendment rather than an informal handshake change. A dental office typically leases in the range of $22 to $38 per square foot annually depending on the market and whether the lease is gross or triple net, and the comparable set should be genuinely comparable: general office space rarely reflects the plumbing, electrical, and structural demands of a working operatory.

Does cost segregation make sense for a dental office?

Frequently, yes, and dental offices are better candidates than most commercial buildings because of how much specialized infrastructure sits inside the walls. A cost segregation study is an engineering-based analysis that breaks the building’s total cost into components and reclassifies the ones that qualify as shorter-lived property under IRC 168, rather than leaving the entire structure depreciating over the standard 39-year nonresidential real property schedule.

Specialized plumbing for suction lines, compressed air distribution, and vacuum systems throughout each operatory typically qualifies as 5-year or 7-year property rather than structural 39-year plumbing, because it serves the equipment rather than the building’s general occupancy. Dedicated electrical circuits for X-ray units, CBCT scanners, and compressors are treated the same way. Built-in cabinetry and casework in each operatory is typically 7-year property, and site improvements such as parking, exterior lighting, and signage are typically 15-year property. Specialty flooring and certain interior partitions can also fall into shorter classes depending on how they are installed.

A study on a typical dental office building reclassifies 20% to 35% of total building cost out of the 39-year bucket. Under IRC 168(k), made permanent at 100% by the One Big Beautiful Bill Act (OBBBA, signed July 4, 2025), everything reclassified into a recovery period of 20 years or less is eligible for full first-year bonus depreciation. The land itself is never depreciable, and the reclassified components have to be separately identified and substantiated by the engineering study, not estimated.

The interaction with the self-rental rule matters here more than almost anywhere else. A cost segregation study is most valuable when it produces a large first-year loss, but a large loss from a self-rental is exactly the outcome the passive activity rules trap unless the grouping election was already in place. Confirm the election has been made before commissioning a study, or the accelerated depreciation may sit suspended for years with no current benefit. The mechanics of Section 179 and bonus depreciation for practice equipment, as distinct from the building itself, are covered in the equipment deductions guide.

Should the lease be structured as triple net?

A triple net lease, where the tenant pays base rent plus property taxes, insurance, and maintenance directly or as a reimbursement, is the most common structure for a self-rental and simplifies the accounting on both sides. The building LLC receives a cleaner, more predictable rental income stream, and the practice, already paying for utilities and day-to-day upkeep, absorbs the additional pass-through costs without much friction. The lease should spell out which party handles structural repairs versus routine maintenance, how property tax reassessments are handled, and how capital improvements like a new roof are allocated. Leasehold improvements the practice pays for directly are generally depreciated by the practice as qualified improvement property rather than added to the building LLC’s basis, since the practice funded and owns the improvement for tax purposes.

What property tax and insurance considerations apply?

Property tax reassessment is worth planning around at the moment the real estate LLC is formed and the building is transferred into it, because in many states a transfer between related entities can trigger a reassessment even without a change in beneficial ownership. This is a state-law question that varies significantly and should be checked with local counsel before the transfer, not after the tax bill arrives.

Insurance needs to be restructured too. The real estate LLC should carry its own property and general liability coverage as the building owner, separate from the practice’s professional liability coverage as the tenant. A single policy that does not distinguish between the two entities can create coverage gaps or undermine the liability separation the structure was built to achieve. Umbrella coverage above both policies is worth discussing with a broker familiar with dental practice structures, since the combined exposure is broader than either entity carries alone.

Can I do a 1031 exchange if I relocate?

Yes, and this is one of the strongest reasons to hold the building in a separate entity rather than inside the practice. A dentist who outgrows the current space or wants a better location can sell the existing building and defer the gain by exchanging into a replacement property under IRC 1031, as long as both properties are held for investment or business use and the exchange follows the identification and closing timelines (45 days to identify a replacement property, 180 days to close) administered through a qualified intermediary.

Because the real estate LLC holds the building independently of the practice, the exchange does not touch the clinical operation. The practice keeps operating, the lease simply moves to the new building once it is acquired, and the gain on the old building is deferred rather than recognized. If the building had remained inside the operating entity, unwinding it for an exchange while the practice keeps running out of the same space would be considerably more complicated, and in some structures may not be practical at all.

Depreciation recapture is the other half of this analysis. Gain attributable to prior depreciation on the building’s structural components is subject to unrecaptured Section 1250 gain treatment (capped at 25%) when the property is sold outright, while gain attributable to components previously reclassified through cost segregation can trigger ordinary income recapture under IRC 1245 if disposed of separately rather than exchanged. A properly structured like-kind exchange of the entire property defers both categories of gain.

What related-party rules under IRC 267 should I watch for?

IRC 267 governs transactions between related parties, and it reaches this structure in two ways. First, the matching rule in IRC 267(a)(2) applies when the practice and the real estate LLC use different accounting methods, most commonly when the practice is cash basis and the LLC accrues rent: the practice’s deduction for accrued but unpaid rent is deferred until the LLC actually includes it in income, generally when paid. This rarely matters if rent is paid monthly and on time, but it becomes relevant if rent is deferred to manage cash flow between the two entities.

Second, IRC 267(a)(1) disallows losses on sales or exchanges of property between related parties. This matters if the dentist ever sells the building directly to the practice entity, or restructures ownership between commonly controlled entities, at a loss. The disallowed loss is not gone forever (a related-party buyer who later sells to an unrelated party can offset gain with it under IRC 267(d)), but it cannot be claimed at the time of the transaction. Because the dentist typically controls both entities, any transfer between them should be reviewed for related-party treatment first.

What should I do next?

If the building is currently sitting inside the same entity as the practice, the first question is whether separating it makes sense given the practice’s stage: years remaining before a likely sale, whether liability exposure is a live concern, and whether the building has enough basis remaining to make a cost segregation study worthwhile. If the answer is yes, the sequence matters: form the real estate LLC, transfer or acquire the building into it, execute a market-rate lease, and make the grouping election in that same first year, before commissioning any cost segregation study.

If the building is already separated but the grouping election was never made, review whether the practice has generated, or is likely to generate, a rental loss that would otherwise sit suspended. If the practice is planning to relocate in the next few years, start the 1031 exchange planning early, since the 45-day identification window leaves little room for improvisation once the relinquished property closes.

These companion guides cover the decisions that connect to this one:

• Dental practice entity structure: LLC, S-corp, partnership, and when to change, the clinical-side entity decision that should be settled before layering a real estate LLC alongside it
• Dental practice tax deductions, covering Section 179 and bonus depreciation for the equipment inside the building, as distinct from the building’s own cost segregation treatment
• Dental practice startup costs for a new practice, covering how buildout and leasehold improvement costs are classified when a dentist is building out a new location rather than acquiring an existing building
• Dental practice valuation and sale, covering how a practice sale is structured when the real estate is, or is not, part of the transaction
• Medical practice real estate: lease vs own, a parallel analysis for medical practices weighing the same lease-versus-own decision
• Veterinary clinic real estate ownership, the same self-rental and grouping election mechanics applied to a veterinary practice

Related guides:

• Dental Associate Compensation Buy In Tax Treatment
• Dental Dso Management Agreement Tax Implications
• Dental Hygienist Classification W2 1099 Independent Contractor
• Dental Practice Bookkeeping Overhead Benchmarks
• Dental Practice Entity Structure Llc Scorp Partnership

This guide is general information, not tax advice for your specific situation. Which points apply, and how, depends on your facts.