Every Boerne and Fair Oaks Ranch home carries at least three price numbers at the same time: the Zestimate that appears in a web search, the market value the county appraisal district keeps on file, and the appraisal a lender orders during a purchase. They come from three different systems, built for three different jobs, and they routinely disagree about the same property. This guide explains what each number actually measures, why the gaps exist, and which one to trust when you are pricing a home, writing an offer, or budgeting for the taxes that follow a Hill Country purchase [1][4][5].
| Number | Who produces it | What it measures | What it is used for |
|---|---|---|---|
| Zestimate | Zillow's automated model | A statistical estimate from public records, MLS history, and user-submitted details | Screening and ballpark context, not an appraisal [1] |
| Tax market value | County appraisal district (Kendall CAD for Boerne, Bexar Appraisal District for San Antonio) | Mass-appraised opinion of market value each January 1 under Tax Code 23.01 | Property tax calculations [4] |
| Lender's appraisal | Licensed appraiser hired by the mortgage lender | Property-specific opinion of market value via the Uniform Residential Appraisal Report | Loan underwriting and collateral value [5] |
The same house can legally carry all three numbers at once. Disagreement between them is normal; the practical skill is knowing which number does which job.
The Zestimate: a statistical model, not an appraisal
The Zestimate is produced by a computer model, not by a person who has seen the property. Zillow feeds public property records, MLS data, and user-submitted details into a proprietary valuation algorithm, and the estimate re-runs automatically as new data arrives [1]. Zillow's own documentation states plainly that the Zestimate is not an appraisal and cannot be used in place of one, and its selling guidance directs homeowners toward a comparative market analysis or a professional appraisal before pricing a home [1][3].
Accuracy is published and worth reading. Zillow reported a median error rate of 1.83 percent for on-market homes nationally in mid-2025, and roughly 1.9 percent for on-market homes in Texas [1][2]. For off-market homes, the national median error jumps to about 7 percent [2]. The Hill Country is a harder case than the national average in a specific way: homes with wells, septic, acreage, outbuildings, and low comparable counts have thinner data, so the model's confidence drops exactly where Boerne and Fair Oaks Ranch get interesting [1].
The county appraisal district value: a tax number, not a sales number
In Texas, the county appraisal district assigns every property a market value as of January 1 of each tax year under Tax Code Section 23.01 [4]. This is mass appraisal: the district values large groups of properties from the tax rolls and sales data, with limited property-specific inspection, and the resulting value exists for exactly one purpose, property taxation [4]. The assessed value that drives your tax bill is that market value reduced by exemptions and caps, and for a residence homestead the appraised value cannot rise more than 10 percent per year under Section 23.23 [4].
The part that surprises new buyers is that the cap does not transfer. When a home sells, the new owner starts fresh, and the appraisal district normally reappraises the property toward the sale price the following January [4]. The seller's bill, based on a capped value, is frequently far below what the new owner will pay. That mechanism is covered in depth in the site's ad valorem tax shock guide and the Texas homestead exemption guide.
The lender's appraisal: the number that gates the loan
When a buyer applies for a mortgage, the lender orders an appraisal to verify the property's collateral value. This is a property-specific opinion prepared by a licensed appraiser who inspects the home and analyzes current sales, and in Texas residential lending it is reported on the Uniform Residential Appraisal Report under Uniform Appraisal Dataset standards [5].
Under the sales comparison approach, the appraiser must present at least three closed sales of the most similar homes available, prefer comparable sales from the same market area, and favor settled sales within roughly the past year [5][6][7]. Adjustments for differences in size, condition, and amenities must reflect what the market actually pays, and the appraiser must review the prior sale history of both the subject property and the comparables [6][7]. The result is an opinion of market value as of the inspection date, and the lender lends against that number [5].
This is where the purchase price meets reality. If the contract price exceeds the appraised value, the buyer brings the difference in cash, the price gets renegotiated, or the buyer exercises the option to terminate. In the current Boerne and Fair Oaks Ranch market, most homes sell at or near appraised value because pricing errors get negotiated before anyone signs a contract, not after.
Where the 2026 market actually sits
Valuation does not happen in a vacuum, and 2026 looks different from 2021 or 2022 on nearly every metric. Published figures vary by source and month, but the direction is consistent: more inventory, longer marketing times, and more room to negotiate than in recent years [8][9][11][13].
| Market | Median sale range | Price negotiations | Inventory and pace |
|---|---|---|---|
| Boerne (78006) | Roughly $575K to $668K by source [8][9][11] | List-to-sale ratio reported near 93 percent in late-2025 data [13] | Median days on market roughly 72 to 94; active listings climbed to about 900 in early 2026 from roughly 287 a year earlier [13][9] |
| Fair Oaks Ranch (78015) | Roughly $712K to $785K [10][14] | Median sale near 4 percent below the original list price in the tracked period [14] | Roughly 50 to 60 active listings and 3.0 to 4.3 months of supply; median days on market about 51 to 100 [14][10] |
Figures differ by source, ZIP boundary, and month. They describe market conditions, not the value of any specific home. Verify against the current listing data for the property you are buying or selling.
For buyers, the practical effect is that offers at a modest discount to list are no longer unusual, and a low appraisal no longer ends the conversation in most cases. For sellers, pricing precision is now the difference between a fast sale and a 90-day listing, and the list price needs to come from current comparable sales, not from a Zestimate or last year's neighbor sale. The site's recent Boerne housing market update and the segment-level micro-market trends report break the numbers down by neighborhood and price band.
How to use each number
- •The Zestimate is a screening tool. It is fine for a first ballpark, weak on acreage and custom homes, and never a substitute for comparables. Zillow's own guidance says the same [1][3].
- •The tax value is a budgeting number, not a pricing number. It shows what the current bill is based on. The buyer's real bill after a purchase is a separate calculation, detailed in the tax shock guide [4].
- •The lender's appraisal is the binding number at closing. Both sides should sanity-check the contract price against the expected appraised value before signing [5].
- •A comparative market analysis by a local licensed agent is the practical pricing tool for listing decisions. It is built from current closed and pending sales in the same neighborhood, which automated models do not fully capture in thin-data markets [3].
Frequently asked questions
Can I trust the Zestimate for a Boerne or Fair Oaks Ranch home?
As a first screening, yes; as a pricing tool, no. Zillow's published median error is about 1.9 percent for on-market Texas homes and about 7 percent for off-market homes, and both figures assume solid comparable data [1][2]. Hill Country acreage and custom homes are the cases where the error runs largest, so treat the number as the start of the conversation, not the answer [1].
Why is the county tax value so different from the list price?
The tax value is a mass appraisal frozen at a January 1 date, while the list price is a seller's current asking number [4]. Add the 10 percent homestead cap, which holds the taxable value below market for long-time owners, and the two numbers can sit apart by a wide margin. On a sale, the appraisal district resets the value toward the purchase price [4].
Will the lender's appraisal match my offer price?
Not automatically. The appraiser builds an independent opinion from at least three closed comparables, market-similar properties, and defensible adjustments [5][6][7]. In a balanced market most contracts close at or near appraisal. In a hot market, or on a truly unique property, an appraisal gap is a real risk that should be planned for before the offer is written.
If the appraisal comes in low, what happens?
Three outcomes are standard in Texas: the buyer brings the difference in cash, the parties renegotiate the price toward the appraised value, or the buyer terminates during the option period [5]. The Texas option period guide explains how the timing works for out-of-state buyers.
The bottom line
No single number tells you what a Hill Country home is worth. The Zestimate is a model with published error bars, the county value is a tax number that resets on sale, and the lender's appraisal is the binding figure at closing. Use the Zestimate to shortlist, use the tax value to budget, and let current comparable sales, in the form of a professional comparative market analysis and a solid appraisal, set the price.
Sources
- Zillow, "What is a Zestimate?" How the Zestimate is calculated, Zillow's statement that it is not an appraisal, and national median error rates for on-market homes. zillow.com
- Zillow, Zestimate accuracy data. Median error rates including about 1.9 percent for on-market Texas homes and roughly 7 percent for off-market homes nationally. mortgage.zillow.com
- Zillow, "How to Price Your Home to Sell." Zillow's own guidance to start with the Zestimate as a ballpark and refine with comparables, a comparative market analysis, or an appraisal. zillow.com
- Texas Comptroller, "Valuing Property." Market value appraisal each January 1 under Tax Code Section 23.01 and the 10 percent homestead cap under Section 23.23. comptroller.texas.gov
- Fannie Mae Selling Guide, B4-1.3-07, Sales Comparison Approach Section of the Appraisal Report. Uniform Residential Appraisal Report requirements for appraising residential property for mortgage lending. selling-guide.fanniemae.com
- Fannie Mae Selling Guide, B4-1.3-08, Comparable Sales. The minimum three closed comparable sales and the preference for sales in the same market area within roughly a year. selling-guide.fanniemae.com
- Fannie Mae Selling Guide, B4-1.3-09, Adjustments to Comparable Sales. Market-based adjustment requirements and prior sale history review. selling-guide.fanniemae.com
- HAR.com, ZIP 78006 price trends. Zip-level median price trends for the Boerne 78006 geography. har.com
- Redfin, Boerne housing market. Median sale price, days on market, and inventory estimates for Boerne. redfin.com
- Redfin, Fair Oaks Ranch housing market. Median sale price, months of supply, and competition data for Fair Oaks Ranch. redfin.com
- Summers Real Estate, "Boerne Real Estate Market: Reading the Latest Trends." SABOR-based Boerne county and ZIP market statistics. summersre.com
- Weigand Real Estate, "Investing in Boerne TX Real Estate: 2026 Market Data." 2026 Boerne market data including list-to-sale behavior and inventory. weigandrealestate.com
- My Boerne Home, "Boerne Market Report: Inventory Up, Prices Down in 78006 & 78015." Active listing counts, days on market, and list-to-sale ratio changes for both communities. myboernehome.com
- Movoto, Fair Oaks Ranch market trends. Months of supply, active listings, and sales-price behavior for Fair Oaks Ranch. movoto.com
The Zestimate, tax values, appraisals, and market figures in this article are general education, not a value estimate for any specific property. Sources publish different boundaries and months, so verify current numbers against the specific home and the current market before making a pricing, offer, or tax decision.
Last verified: September 15, 2026
Published: September 15, 2026
Updated September 15, 2026