How to set land value for rental depreciation

The most common way to set land value for a rental is to take the county assessor’s land-to-total ratio and apply it to your purchase price. An appraisal, comparable land sales, or an allocation in the purchase contract can also work, and they’re better when the assessor’s split looks wrong. A flat percentage picked because “everyone uses 20%” is the weakest option, and it can cost you real deductions.

Why land value matters

Land doesn’t wear out, so it can’t be depreciated. Everything you paid for a rental gets split into two piles: land, which stays on your books untouched until you sell, and the building, which you depreciate. A cost segregation study only works on the building pile. Every dollar you assign to land is a dollar that will never produce a deduction while you own the property.

That cuts both ways. Set land too high and you give up deductions. Set it too low and you’ve overstated depreciation, which is one of the first things an examiner checks.

Method 1: assessor ratio applied to the purchase price

Most counties value land and improvements separately for property tax. Those dollar figures often lag the market, so don’t use them directly. Use the ratio between them.

An illustration. You buy a rental for $420,000. The county assessment shows:

Assessor line	Value
Land	$90,000
Improvements	$210,000
Total	$300,000

Land is $90,000 ÷ $300,000 = 30% of the assessed total. Apply that to what you paid: $420,000 × 30% = $126,000 of land, and $420,000 − $126,000 = $294,000 of building.

If you had used the assessor’s $90,000 land figure as is, you’d have assigned $330,000 to the building and overstated it by $36,000. The ratio method avoids that.

Capitalized closing costs get split the same way. If you had $6,000 of title, recording and transfer costs, 30% ($1,800) goes to land and 70% ($4,200) to the building, for a depreciable basis of $298,200.

Use the assessment for the year you bought, or the closest one to it. Save a copy of the page, because the county website will show a different year next time you look.

Method 2: an appraisal

An appraiser can value the land separately from the house. Appraisals done for your mortgage usually include a site value, though lenders’ appraisers don’t always support it in detail. A separate appraisal costs more, but it’s the strongest evidence you can have if the assessor’s split looks wrong.

Method 3: comparable land sales

Recent sales of vacant lots in the same neighborhood, adjusted for size and location, show what the land under your house is worth. This works in areas with enough lot sales to compare. In a fully built-out suburb there may be none, and in a rural area the comparable lots may be very different from yours.

Method 4: an allocation in the purchase contract

Buyer and seller can agree on a land and building split in the purchase agreement. The IRS gives weight to allocations negotiated at arm’s length between parties with opposing interests. In a typical home sale, though, the seller doesn’t care how the price is split, so the allocation is only as good as the evidence behind it. If you use this method, base the number on an appraisal or comps, and agree to it before closing.

Why a flat “20%” is weak

Plenty of preparers default to 20% land, or 15%, or 25%, for every rental. It’s easy, and it’s often wrong. Land share varies a lot by place. A house on a big lot in a coastal city can be more than half land, while a home in a rural county may be single digits. A single number can’t fit both.

The IRS Cost Segregation Audit Techniques Guide treats rule-of-thumb figures as a weakness in a study, and that applies to land as much as to the building components. If you’re ever asked how you set land value, “it’s what we always use” isn’t an answer. A dated assessor page and a one-line calculation is.

How much land share changes your savings

Same $500,000 purchase, three land shares. The study reclassifies 30% of the building, all of it taken as 100% bonus, and the owner is in the 32% bracket and can use the losses. Illustrative figures only.

Land share	Land value	Depreciable building	Reclassified (30%)	Year-1 tax effect of the bonus at 32%	Annual straight-line without a study
15%	$75,000	$425,000	$127,500	$40,800	$15,455
25%	$125,000	$375,000	$112,500	$36,000	$13,636
40%	$200,000	$300,000	$90,000	$28,800	$10,909

Moving from 15% to 40% land takes $12,000 off the first-year tax effect and about $4,500 off every year of regular depreciation. The study fee is the same in all three rows, so a high land share also stretches the payback. Is cost segregation worth it? runs the full break-even test.

Condos

A condo owner owns the unit plus a share of the common elements. The land sits inside that common interest, shared with every other owner in the building. So a condo’s land share is usually smaller than a detached house’s, often much smaller in a mid-rise or high-rise. Some assessors assign each unit a land value, and some don’t separate it at all. If yours doesn’t, the declaration’s percentage interest in the common elements and the county’s treatment of comparable units are reasonable places to start. This is one reason condos often produce a higher reclassification percentage than houses.

When to get an appraisal

The assessor ratio is fine for most rentals. Consider an appraisal when:

• The assessor’s split looks out of line with what lots actually sell for nearby.
• The county hasn’t reassessed in years, or assigns a land value that doesn’t match recent sales.
• You did a major renovation the assessment doesn’t reflect yet.
• Land is a large share of the price and a few points either way change the deduction by more than the appraisal costs.

We use county assessor data to support the land and building split unless you have a better figure, so an appraisal isn’t required for a study. If you have one, send it.

What to do next

Look up your county assessment for the year you bought, work out the land ratio, and apply it to your price. Then put the result into the rental property depreciation calculator and compare it with whatever percentage your current depreciation schedule uses. If they differ by a lot, raise it with your CPA. When you’re ready, a free proposal shows the study fee and estimate. Our document checklist lists what else to gather.

This is general information, not tax advice. Your CPA should confirm how it applies to you.