What Counts as a Land Improvement, and Why Does It Depreciate Over 15 Years?

TL;DR: A land improvement is anything built on the dirt that is not the building itself. The parking lot, the sidewalks, the fence, the landscaping, the site lighting, the storm drains. The IRS puts those in their own asset class, separate from the building, and that class depreciates over 15 years instead of 39. Because 15 years sits under the 20-year ceiling for bonus depreciation, land improvements are generally bonus-eligible, which means the parking lot can often be written off entirely in the first year. What they do not qualify for is Section 179, and that is the single most common mistake I see on this topic.

Key Takeaways

• Land is never depreciable. Improvements made to land are, and they live in their own class rather than inside the building.
• The authority is asset class 00.3 of Revenue Procedure 87-56, which covers sidewalks, roads, drainage facilities, sewers, fences, landscaping and more.
• Recovery period is 15 years under the general depreciation system and 20 years under the alternative depreciation system.
• The method is 150 percent declining balance, not straight line, so the early years are front-loaded even before bonus depreciation touches them.
• Land improvements qualify for bonus depreciation because their recovery period is 20 years or less. Buying an existing building counts, as long as the used property rules are met.
• Land improvements are not Section 179 property. IRS Publication 946 says so in a single sentence.
• On a building you bought rather than built, the land improvements came bundled into one purchase price. Separating them takes an engineering-based study, not an estimate.

What is a land improvement, in the IRS's own words?

Start with the definition, because almost every argument about land improvements is really an argument about what belongs in the bucket.

The IRS Cost Segregation Audit Techniques Guide, Publication 5653, states it directly: "Asset Class 00.3 of Rev. Proc. 87-56 describes land improvements as depreciable improvements made directly to or added to land, whether such improvements are § 1245 property or § 1250 property. Examples of land improvements include sidewalks, roads, canals, waterways, drainage facilities, sewers, wharves and docks, bridges, fences, landscaping, shrubbery, and radio and television transmitting towers. Buildings and structural components are specifically excluded from the category of land improvements."

Two things in that sentence do a lot of work.

The first is the phrase "made directly to or added to land." That is the test. If it improves the site rather than the structure, it is a land improvement. Paving, curbs, exterior lighting on poles, retaining walls, irrigation, security fencing, the storm drain system under the parking lot.

The second is the exclusion. Buildings and structural components are out. The roof is not a land improvement. The exterior wall is not a land improvement. Lighting mounted on the building to illuminate the building is a structural component, while lighting on a pole in the parking lot is not. That line is finer than it looks, and getting it wrong in either direction is what a documented study exists to prevent.

Land itself never depreciates. It does not wear out, so the code gives you nothing for it. Everything you built on top of it is a different question.

Why does a parking lot depreciate over 15 years when the building takes 39?

Because the recovery period comes from the asset's class life, and land improvements were assigned a shorter one.

Internal Revenue Code Section 168(e)(1) sorts property into classes by class life. Property with a class life of "20 or more but less than 25" years is 15-year property. Land improvements in asset class 00.3 carry a class life of 20 years, which drops them squarely into the 15-year bucket. Section 168(c) then sets the recovery period for 15-year property at 15 years.

Nonresidential real property gets 39 years under that same table. Residential rental gets 27.5. So the identical dollar, spent on asphalt instead of on drywall, comes back to you more than twice as fast.

There is a second acceleration most owners never notice. Section 168(b)(2)(A) applies the 150 percent declining balance method to "any 15-year or 20-year property," while buildings are stuck on straight line. Declining balance front-loads the deduction. Even in a world with no bonus depreciation at all, a parking lot would still hand you more in year three than a straight-line schedule would.

Under the alternative depreciation system the same assets stretch to 20 years. That matters if you have elected out of the business interest limitation as a real property trade or business, because that election forces ADS and takes bonus depreciation off the table for the property it covers. Worth knowing before you make it, not after.

Can you take 100 percent bonus depreciation on a parking lot?

Generally yes, and this is where the money is.

Bonus depreciation reaches property whose recovery period is 20 years or less. The Treasury regulations on the additional first year depreciation deduction, finalized in 2019, list the categories plainly: qualified property must be, among other options, "MACRS property that has a recovery period of 20 years or less." Fifteen-year land improvements clear that bar without effort. The 39-year building never will.

How much bonus you get depends on when you acquired the property. IRS Publication 946, 2025 revision, describes the current rule: "P.L. 119-21, commonly known as the One Big Beautiful Bill Act, reinstated the 100% special depreciation allowance for certain qualified property acquired and placed in service after January 19, 2025." Property acquired before January 20, 2025 sits under the old phase-down instead, which was 40 percent for property placed in service during 2025.

Now the part that surprises buyers. You do not have to have built the parking lot to write it off. Bonus depreciation has covered used property since 2017, so buying an existing building buys you its land improvements too. The IRS lists five conditions for used property in its bonus depreciation guidance: the property was not used by you or a predecessor before the acquisition, it was not acquired from a related party or a member of a controlled group, your basis is not determined in whole or in part by the seller's adjusted basis, your basis is not determined under the rules for property acquired from a decedent, and the cost does not include the basis of other property you already held.

Read that fourth condition again if you inherited the building. Property that takes a stepped-up basis from a decedent does not meet the used property test, so bonus depreciation is off the table for it. The stepped-up basis is usually the better deal anyway, and I went through why in how a stepped-up basis nullifies cost segregation recapture.

One more decision sits on top of all of this. Bonus depreciation is automatic, and taking the whole thing in year one is not always the best outcome. The land improvements are their own class, so you can decide about them separately from the five-year property in the same building. I worked through when that trade is worth making in when you should elect out of bonus depreciation.

Can you use Section 179 on land improvements?

No, and this is the one I correct most often.

Publication 946 leaves no room: "Land and land improvements do not qualify as section 179 property. Land improvements include swimming pools, paved parking areas, wharves, docks, bridges, and fences."

That sentence is worth reading twice, because plenty of otherwise careful writing on this subject says the opposite. Section 179 and bonus depreciation both produce a first-year write-off, they get discussed in the same breath, and it is easy to assume that anything eligible for one is eligible for the other. On land improvements that assumption is simply wrong.

The practical effect is small when bonus depreciation is at 100 percent, because bonus gets you to the same place. It stops being small the moment bonus is not available. A taxpayer over the Section 179 income limitation, a business in a year with no taxable income, or property acquired under a pre-2025 binding contract can all end up reaching for Section 179 on the parking lot and finding nothing there. Plan around it rather than discovering it on the return.

If you are sorting out which of the two applies to what, I laid the comparison out in bonus depreciation versus Section 179.

How much of a building's purchase price is land improvements?

It depends entirely on the property, and anybody who answers that question without seeing the site is guessing.

A strip center with two acres of parking and a lit sign pylon has a very different profile from a downtown office tower with no surface lot at all. A mobile home park is mostly land improvements by construction, which is why those studies produce the results they do, and I wrote that one up in why mobile home park studies yield 80 percent accelerated depreciation. A self-storage facility, a car wash, an apartment complex with structured parking: all different again.

The reason the number cannot be guessed is more interesting than the number itself. When you buy an existing property, you pay one price. Nobody hands you an invoice that says $310,000 for paving. The allocation has to be reconstructed from the property as it actually stands, priced against real construction cost data, and written down in a form that survives a question. That reconstruction is the study.

This is exactly why I will not write about desktop studies and rule-of-thumb percentages as though they were a lesser version of the same thing. They are a different thing. A percentage applied to a purchase price produces a number on a page. An engineering-based study, built from the construction documents and an in-person site visit by a trained professional, produces a number with the work shown underneath it. When an examiner asks how you arrived at $310,000 of paving, only one of those two answers is an answer. I made the full case in why engineering-based cost segregation is the only kind worth doing, and we talked through the misconceptions on the podcast in cost segregation myths versus reality.

What happens to land improvements when you sell?

The acceleration comes back. That is not a catch, it is the nature of the deal, and it belongs in the decision up front.

Cost segregation moves deductions forward in time. It does not create new ones. Every dollar you take early reduces your basis, and a lower basis means more gain when you sell. How that gain is taxed depends on what the asset is, and land improvements are unusual here because the class contains both kinds. The audit guide says so explicitly: asset class 00.3 covers improvements "whether such improvements are § 1245 property or § 1250 property."

A paved parking area is not tangible personal property. Treasury Regulation 1.48-1(c), which the classification rules still run through, states that "buildings, swimming pools, paved parking areas, wharves and docks, bridges, and fences are not tangible personal property." Other items in the same class land on the other side. The character of the recapture follows that split, and the arithmetic differs enough that it is a conversation with your CPA rather than a rule of thumb.

What I will say plainly is this: if a sale is on your calendar inside the next two or three years, run the sale math before you take the deduction. I walked through how that plays out in what happens when you sell a property after cost segregation.

What if you have owned the property for years already?

Then the land improvements have been depreciating over 39 years the whole time, and you can fix that without amending anything.

A look-back study reclassifies the components as they should have been classified from the start, and the entire catch-up comes through as a deduction in the current year by way of an automatic accounting method change on Form 3115. No reopened returns. For an owner who has held a commercial property for eight or ten years with a large parking lot sitting in the 39-year bucket, that catch-up is often the biggest single line on the return.

I covered the mechanics in the look-back study guide, and the documents a study actually needs in what documents you need for a cost segregation study.

FAQ

Is a parking lot a land improvement? Yes. A paved parking area is a land improvement under asset class 00.3 of Revenue Procedure 87-56, which means it depreciates over 15 years under the general depreciation system rather than over the 39 years that applies to nonresidential buildings.

How long do land improvements depreciate? Fifteen years under the general depreciation system and 20 years under the alternative depreciation system. The method under GDS is 150 percent declining balance, switching to straight line when that produces a larger deduction.

Do land improvements qualify for bonus depreciation? Generally yes. Bonus depreciation applies to MACRS property with a recovery period of 20 years or less, and land improvements have a 15-year recovery period. How much you get depends on when the property was acquired, with 100 percent available for qualified property acquired and placed in service after January 19, 2025.

Can you take Section 179 on land improvements? No. IRS Publication 946 states that land and land improvements do not qualify as section 179 property, and it names swimming pools, paved parking areas, wharves, docks, bridges, and fences as examples.

Can you depreciate land improvements on a building you bought rather than built? Yes. The land improvements came with the purchase, and separating them from the building requires an allocation of the purchase price. Bonus depreciation is available on used property when the acquisition meets the five conditions in the IRS guidance, including that your basis is not carried over from the seller and not determined under the rules for property acquired from a decedent.

The parking lot is not a rounding error

Most owners think of a cost segregation study as being about what is inside the building. The carpet, the cabinetry, the specialty electrical. Those matter. But on a lot of properties the largest single reclassification is sitting outside the front door, under everyone's tires, depreciating at a quarter of the speed the law allows.

Congress wrote the 15-year class on purpose. Using it is not a loophole and it is not aggressive. Tax evasion is a crime, and tax avoidance is mandatory. The only real question is whether anyone has ever looked at your property closely enough to tell you what is out there.

If you own a building, or you are about to, the no-cost analysis tells you what a study would find and what it would be worth before you commit to anything. No obligation and no pitch, and nothing for you to gather beforehand. If a study will not pay for itself on your property, I will say so and save you the fee.

Grab a time on Calendly at calendly.com/david-wiener/cs or call 770-224-8504, option two. Details on the service are at davidhwiener.com. Cost segregation, 179D, and R&D credit studies are delivered through my relationship with CSSI (Cost Segregation Services, Inc.), whose team also wrote up how to calculate depreciation for land improvements.

This article is educational and is not tax, legal, or accounting advice. Every situation is different; work with a qualified tax professional before acting on any strategy described here.