Insight
How Texas CADs Actually Value Commercial Property
And Where the Evidence Breaks Down
Texas Central Appraisal Districts are required by law to determine the market value of every commercial property in their jurisdiction as of January 1 each year. They use three standard approaches: cost, income, and sales comparison. That's the textbook version. The reality is different.
After more than two decades of reviewing CAD evidence, challenging their valuations, and cross-examining their appraisers in arbitration hearings, I can tell you that the system has fundamental structural problems that most commercial property owners never see. Not until someone shows them where to look.
This article walks through each approach the way the CAD actually applies it, not the way the appraisal textbook describes it, and identifies the specific points where the evidence breaks down. If you own or operate commercial property in Texas, understanding these mechanics is the first step toward knowing whether your assessment reflects reality or a model that hasn't been updated to match it.
The Cost Approach: CAMA and the Black Box
Texas CADs don't perform property-specific cost analyses. They run a system called CAMA, which stands for Computer Assisted Mass Appraisal. It's a software-driven model that takes a handful of property characteristics (building class, construction type, square footage, year built) and produces a replacement cost estimate, depreciation calculation, and final value conclusion. The entire process is automated. No human sits down with your property's blueprints, walks the building, or analyzes the output before it becomes your assessed value. The system runs, the number prints, and that's what shows up on your notice.
What makes this difficult to see from the outside is that the starting point is actually reasonable. The CAD's base cost rates, the per-square-foot replacement cost before any adjustments, are generally within 10% of what you'd find in Marshall & Swift (MVS), the professionally recognized cost authority used by appraisers, lenders, and insurers across the U.S. and Canada. If the process stopped there, you'd have a defensible number. It doesn't stop there.
Immediately after the base rate, the CAD's model departs into a black box of proprietary adjustments. These adjustments have no published support, no external validation, and no demonstrated relationship to actual market behavior. Three categories do the most damage: cost multipliers, depreciation schedules, and market index adjustments. Each one layers unsubstantiated assumptions onto a reasonable starting point until the final number bears little resemblance to what a credentialed appraiser, or the market itself, would conclude.
Depreciation Schedules
The CAD's depreciation tables are where the model most visibly detaches from reality. These proprietary schedules, in practice, routinely classify buildings that are 60 to 80 years old as 50% to 60% “good,” meaning the model assumes these structures have retained half or more of their original value. For a 1960s metallic warehouse or a 1970s suburban office building, that conclusion defies both common sense and professional appraisal standards.
Worse, the depreciation applied is almost entirely physical, limited to the wearing out of components over time. There is typically no meaningful consideration for functional obsolescence, economic obsolescence, or external obsolescence. This is a critical gap, because virtually every commercial property older than 30 years suffers from functional obsolescence. These buildings were designed for a different era. The technology requirements were different. The building codes, tenant expectations, and market conditions were all different.
Real-World Example: Westheimer Road Car Wash
Consider a car wash property on Westheimer Road in Houston, originally built in 1986. This single property illustrates three layers of obsolescence the CAD's depreciation schedule treats as invisible.
- Functional obsolescence: The property was designed for a full-service car wash model that is now outdated. Modern express-wash facilities are engineered for higher throughput, automated systems, and a fundamentally different customer experience. The 1986 design cannot compete without substantial renovation.
- Economic obsolescence: The Westheimer Road corridor is saturated with modern car wash competitors. The subject competes against newer, purpose-built facilities that attract the same customer base at lower operating costs.
- Superadequacy: The property includes a mini-lube component that occupies space on the site but reduces the property's competitive utility for its primary car wash function. Space dedicated to a use that doesn't contribute proportional value is superadequacy.
The CAD's depreciation schedule treats all three as invisible. The model produces a value conclusion that assumes a 1986 car wash is functionally equivalent to a 2024 express facility, competing on equal footing in a saturated corridor. That's not depreciation analysis. That's the absence of one.
Market Index Adjustments
After applying its depreciation schedule, the CAD layers on a market index adjustment, sometimes called a market modifier or cost multiplier. This factor is supposed to align the cost conclusion with actual market conditions. In theory, it's derived from sales data: the CAD compares cost model outputs to sale prices and calculates a ratio to close the gap.
In practice, these adjustments are built on sales that may be years old, drawn from across the entire county, with no demonstrated correlation to the specific property, property type, age, or submarket being valued. A market index multiplier calibrated using 2022 sales of Class A industrial buildings in northwest Houston has no relevance to a 1968 low-utility warehouse in the southwest corridor, but the CAMA system doesn't make that distinction. It applies the factor and moves on.
No Human in the Loop
This is the point that most property owners miss entirely. The CAMA system is not a tool that assists an appraiser in forming an opinion. It is the opinion. The system ingests property characteristics, applies its proprietary schedules and multipliers, and outputs a value. No appraiser reviews the output for reasonableness before it posts to the tax roll. No one cross-checks whether the depreciation schedule makes sense for your specific building. The number prints, and it becomes your assessed value. It stays that way until someone challenges it.
Operator Logic
Under Texas Tax Code §41.461, property owners have the right to request the evidence the CAD intends to rely on, including cost tables, depreciation schedules, land tables, formulas, and underlying model data. In practice, when property owners make these formal requests, the CAD routinely fails to provide the underlying schedules and formulas. A mass-appraisal model whose underlying data is withheld even when legally requested is not a transparent valuation. It is a black box that the property owner is expected to accept on faith.
The CAD's CAMA cost model is not recognized by any appraisal professional, lender, insurer, or valuation firm as a credible cost methodology. It is not published, peer-reviewed, or benchmarked against industry standards. By contrast, Marshall & Swift, the authority most CAD base rates are loosely derived from, is rigorously tested and validated against real-world construction data, written into legislation or administrative rule in more than 30 states, and continuously updated with verified market data.
The most telling evidence is what happens when the cost approach is actually challenged. When a property owner presents credible evidence, the district abandons its own cost output during settlement negotiations. They don't defend it. They don't reconcile it. They move to a number that can be justified, almost always significantly lower than what the CAMA model produced. When the entity that built the model won't stand behind it under scrutiny, that tells you everything you need to know about its reliability.
The Income Approach: Your Property's Financials, According to Someone Who's Never Seen Them
The income approach is the one most commercial property owners expect to see, and the one that often appears most credible on the surface. The CAD estimates market rent for your property, applies a vacancy and collection loss factor, subtracts operating expenses, and capitalizes the resulting net operating income using a capitalization rate. The math is straightforward. The inputs are where it falls apart.
Market Rent
The CAD does not use your actual lease rates. They apply “market rent” derived from surveys, vendor databases like CoStar, or internal studies that may be years old. Your property might have below-market leases due to tenant concessions, a weak submarket, or a business decision to retain a long-term tenant at a lower rate. None of that is reflected.
Evidence Gap: Greenspoint/North Belt Corridor
A fee appraisal analyzed actual lease comparables and found rents ranging from $9 to $15 per square foot NNN, concluding $12.50/SF. HCAD's income model for a 70,548 SF strip center in the same corridor applied $13 per square foot at 93% stabilized occupancy. The property was 46% occupied, and stabilized market occupancy was approximately 83%. When the income approach starts with inputs disconnected from the market, every calculation that follows inherits the error.
Expense Ratios
The CAD applies standardized expense ratios, typically in the 33% to 35% range for most commercial property types. Your property might run a 42% expense ratio because of aging mechanical systems, high insurance costs, or a management-intensive tenant mix. The CAD plugs in what their model says your property type should run. Your actual profit-and-loss statement does not enter the equation. The result is that the CAD's modeled net operating income is higher than your actual NOI, which means their value conclusion is higher than what an informed buyer would pay based on real cash flow.
Vacancy and Occupancy
This is where the model fails most visibly. CADs often apply stabilized vacancy assumptions, typically 5% to 15%, across entire submarkets or property types, regardless of what is actually happening on the ground.
Real-World Example: Bank of America, Greenspoint Corridor
The Greenspoint/North Belt office submarket runs 46% to 49% vacancy, the highest among major Houston submarkets, against a broader Houston MSA average of approximately 25% to 27%. Greenspoint Mall closed permanently in June 2024 after 48 years of operation.
A Bank of America branch in the corridor: a 37,719 SF two-story office building on a pad site within the former Greenspoint Mall footprint. Bank of America renewed its lease in 2023 but cut its footprint to just 16,871 SF, vacating the entire second floor. Occupancy dropped to 44.73%. The second floor has remained vacant for approaching three years with no recorded tenant interest.
HCAD's income model applied $18/SF in rent and 81% occupancy. Nearby, a 190,000 SF office building sold at auction for $16/SF at 9% leased, and a 156,000 SF medical office building sold for $16/SF at 32% leased. When the district projects stabilized occupancy onto a building that is nearly half empty in a submarket where half-empty is the norm, the valuation has no evidentiary foundation.
Cap Rates
The capitalization rate is the single most impactful variable in the income approach. A shift of 50 to 100 basis points on a property with meaningful NOI can move the assessed value by hundreds of thousands of dollars. Yet the CAD's cap rate selection is often opaque. The rate is cited as “market-derived” without clear documentation of which sales informed it, what operating data was extracted, what adjustments were made for property-specific risk, or why that rate applies to your property rather than a different one.
Some districts produce their own cap rate studies as supplementary evidence. These studies compile transaction data and extract capitalization rates from market sales. But the cap rate applied in the model and the cap rate supported by the district's own study are not always the same number. A 50 to 100 basis point difference between the study and the model is not unusual, and most property owners never catch it because they do not know the study exists or where to find it in the evidence packet.
Operator Logic
In many cases, the cap rate appears selected to confirm, rather than derive, the final value. The CAD knows approximately where they want the value to land. They select a cap rate that gets them there. On the Bank of America building in Greenspoint, the district applied a 10.44% cap rate. Whether that rate reflects the actual risk profile of a nearly half-vacant office building on a dead mall pad in the most distressed submarket in Houston is a question the CAD's evidence never answers. That is not appraisal. That is arithmetic arranged to reach a predetermined answer.
The Sales Comparison Approach: A Data Dump Disguised as Analysis
The sales comparison approach is the most intuitive valuation method: find properties that sold recently, adjust for differences, and use those adjusted prices to estimate market value. In residential appraisal, this approach typically drives the conclusion. In commercial property valuation at the CAD level, it rarely functions as an independent analysis.
What the CAD presents as a “sales comparison approach” is typically a raw export from the same CAMA system: a list of sales dumped from the database with no property-specific analysis attached. Some districts produce a more formal Sales Approach Grid, but the result is the same: the grid still backs into the number the CAD already arrived at through the cost and income approaches. The formatting is better, but the analytical foundation is identical.
Look at the supplemental sales list in a typical CAD evidence packet. It includes no adjustments for age, size, quality, construction type, wall height, utility, location, or condition. It includes no screening for comparability to the subject property. A 2018 Class A tilt-wall distribution center appears alongside a 1972 low-utility metallic warehouse as though they are interchangeable. Under Texas Tax Code §23.013, a sales comparison approach requires adjusted comparable sales that reflect the characteristics of the subject property. A list of unadjusted sales does not meet that standard.
Real-World Example: Classification Mismatch
In one Houston arbitration, the CAD classified the subject property, a car wash, as a 4330, Specialized Auto Use, Average quality. The CAD then submitted a supplemental “Retail” sales packet as its market evidence. The packet contained zero sales of Average-quality 4330 properties. Not one. The CAD's own evidence did not contain a single comparable sale matching the property type the CAD itself had assigned. The sales list was never built to support this specific property's valuation. It was a pre-compiled data set, sorted by distance, not by similarity.
There is an additional structural problem baked into the data itself. Low-price sales are routinely discarded as “outliers.” When the CAD compiles its sales list, sales at the lower end of the price range are frequently excluded on the grounds that they represent distressed transactions or unusual circumstances. That screening may sometimes be legitimate, but when it is applied systematically and only in one direction, the result is an upward-biased data set. Any average, median, or range derived from this filtered set will overstate market value.
Operator Logic
The three-approach conclusion that appears triangulated (cost says X, income says Y, sales says Z, and they all converge) looks like validation. But when all three approaches are built on the same CAMA system, use the same stale data, apply the same unverified assumptions, and are adjusted to reach the same conclusion, the “convergence” isn't independent confirmation. It's circular reasoning. Three approaches arriving at the same answer doesn't mean the answer is right. It means the same set of assumptions produced the same result three different ways.
What This Means for You
Your assessment isn't wrong because someone made a data-entry error or transposed a digit. It may be wrong because the entire methodology relies on inputs that don't reflect your property, your market, or your operating reality.
The cost approach starts with a reasonable base rate and then buries it under proprietary depreciation schedules, undocumented multipliers, and market index adjustments that no human reviews and no appraiser can explain. The income approach models your financials using rents, vacancy rates, and expense ratios that may be years old and have never seen your P&L. The sales approach dumps a list of unadjusted transactions into the packet and calls it market confirmation.
You have the right to challenge this. Texas law provides formal protest before the Appraisal Review Board, binding arbitration, and judicial review as mechanisms to correct valuations that don't reflect market reality. But effectively challenging a CAD valuation requires understanding how the evidence was built, and where it breaks. You don't win a property tax dispute by arguing that your value “feels too high.” You win by identifying the specific inputs that are wrong, unsupported, or stale, and presenting better evidence.
By contrast, a property-specific analysis starts with the actual property. It uses a recognized cost authority with published data. It analyzes the actual rent roll, actual expenses, and actual occupancy. It identifies and quantifies functional, economic, and external obsolescence specific to the subject. It adjusts comparable sales for measurable differences. And it arrives at a conclusion through transparent reasoning that can be examined and defended.
That's not a higher standard. That's the standard.
That's what we do.
Joe Gomberg
Property Tax Consultant & Texas Certified General Appraiser
Joe Gomberg has spent over two decades in valuation and property tax work across Texas, with appraisal experience dating back to 2002 and a property tax focus since 2008. He is the President of Champions Property Tax, representing commercial property owners through every stage of the dispute process: informal hearings, ARB, binding arbitration under Texas Tax Code §41A, and litigation support.
Frequently Asked Questions
Can I request the CAD's evidence before my hearing?
Yes. Under Texas Tax Code §41.461, you can request the evidence the CAD plans to present at your ARB hearing. The district is required to provide this before the hearing date, allowing you to see their rent assumptions, cap rates, vacancy factors, cost schedules, and comparable sales before you walk into the room. If you go in without reviewing their evidence first, you're responding to arguments you haven't seen.
What if the CAD can't explain their own adjustments?
This is more common than you'd think. If a CAD appraiser applies a market index adjustment to their cost approach and cannot explain its derivation, including which sales informed it, how it was calculated, or why it applies to your property, that adjustment has no credible foundation. The same applies to income approach inputs. If the appraiser can't explain why they used a 7% cap rate instead of 8%, or where their market rent estimate came from, those aren't supported conclusions. They're assumptions. An unexplained assumption isn't evidence, and it shouldn't survive scrutiny in a hearing or arbitration proceeding.
Which valuation approach is hardest to challenge?
None of them are hard to challenge when the inputs are wrong. The income approach often appears most credible to arbitrators and judges because it looks property-specific. It uses rent, expenses, and capitalization rates that seem tailored to the subject. But as this article explains, the inputs are frequently standardized, stale, or both. A well-prepared challenge can dismantle any approach by exposing the gap between the model and reality. The question isn't which approach is hardest to challenge. The question is whether you have better evidence than the district, and whether you know how to present it.
How do I know if my assessment is based on stale data?
Start with the CAD's vacancy and occupancy assumptions. If your property or submarket has experienced significant vacancy and the CAD's model shows stabilized occupancy at 90% or above, that's an immediate red flag. Next, check their rent assumptions against your actual leases and against current market surveys for your submarket. If there's a material gap, for example the CAD models $22 per square foot and your weighted average effective rent is $16, the income approach is built on outdated or inapplicable inputs. Finally, look at the comparable sales in their sales comparison approach. If the most recent sale is two or three years old and market conditions have shifted, the comparison has limited relevance.
Should I hire an appraiser or a property tax consultant?
This question matters more than most people realize, because the two roles are fundamentally different. Property tax consulting is inherently an advocacy role. The consultant's obligation runs to the client. A licensed appraiser performing fee appraisal work, by contrast, is bound by independence and objectivity requirements under USPAP. A consultant who also holds appraisal credentials brings the technical rigor of appraisal training to the advocacy context of property tax work. The right tax consultant will also discuss whether engaging an independent appraiser is the right strategy for your specific situation and why. A fee appraisal from a separate, independent appraiser provides an objective, third-party opinion of value that advocacy work, by definition, cannot. That independence is exactly what gives it weight.
Is this a problem specific to one appraisal district?
No. The structural issues described here, including stale inputs, unexplained adjustments, and standardized assumptions applied to unique properties, exist in mass appraisal systems across Texas. Harris County, Dallas County, Tarrant County, Bexar County, Travis County: every district faces the same fundamental challenge: valuing thousands of commercial properties with limited data, limited staff, and limited time. The core problem is inherent to mass appraisal. It is a system designed to value everything, which means it is not designed to value any single property with the precision that a property-specific analysis would provide. That gap between mass appraisal and property-specific reality is where the opportunity to correct your valuation exists.
What is CAMA and why does it matter for my assessment?
CAMA stands for Computer Assisted Mass Appraisal. It is the software system Texas CADs use to value every property in their jurisdiction. The system takes a set of property characteristics, including building type, size, age, and construction class, and runs them through proprietary cost schedules, depreciation tables, and market adjustment factors to produce a value. The process is fully automated. No appraiser reviews the output for your specific property before it posts to the tax roll. The base cost rates are generally reasonable, typically within 10% of Marshall & Swift. But the layers of proprietary adjustments applied after the base rate can move the final number significantly from where a property-specific analysis would land. Understanding CAMA matters because it reframes what your assessment actually is: not an appraiser's opinion of your property's value, but an automated output that no human has verified against the reality of your building, your market, or your operating conditions.
Related Reading
Insight
Why Most Property Tax Arbitrations Are Won Before the Hearing Starts
How evidence structure, audience awareness, and preparation determine arbitration outcomes under Tax Code §41A.
Case Study
Strategic Valuation Reset: Harwin Drive Portfolio
$1.58M reduction through binding arbitration under Texas Tax Code §41A.