Built a Pool, Shed, Addition, or New Home? How Texas Omitted Property Tax Works
November 4, 2026 | Michael Saegert, Attorney at Law
You built a swimming pool a few years ago. Added a detached garage or shed. Expanded the house. Or perhaps you purchased a property and later discovered that part of an improvement was never included in the appraisal district’s records.
Then a notice arrives saying the property was omitted from a prior appraisal roll.
The immediate questions are usually the same:
Can the appraisal district go back and tax it now? How many years can they go back? And how long do I have to challenge it?
Those questions matter because an omitted-property assessment can create more than a higher value going forward. It can result in prior-year appraisals and unexpected back-tax bills.
If that happens, the matter may involve Texas omitted property tax.
With 2026 Texas property tax bills now being mailed, this is an important time for property owners to understand what an omitted-property notice means and which deadlines may apply.
What Is Omitted Property in Texas?
Omitted property generally refers to taxable property that should have appeared on an appraisal roll but was not included.
Under Texas Tax Code §25.21, a chief appraiser who discovers omitted real property may add it to the appraisal records for any of the three preceding tax years. Personal property generally has a two-year lookback period.
[EXTERNAL LINK → Official Texas Tax Code §25.21]
The property is appraised as of January 1 of each year in which it was omitted.
That distinction is important. An omitted-property assessment is not simply the appraisal district changing this year’s value. It may involve adding property or an improvement that the district says should have been included in earlier years.
Is a New Pool, Shed, Addition, or House Considered Omitted Property?
Potentially, but not automatically.
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Texas property tax law distinguishes ordinary repairs and maintenance from a new improvement that increases a property’s market value.
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Under Texas Tax Code §23.23, a new improvement to a residence homestead generally means an improvement made after the most recent appraisal that increases market value and whose value was not included in the preceding year’s appraisal. Ordinary repairs and maintenance are excluded from that definition.
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Depending on the facts, omitted-property issues may involve the following:
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A Newly Built House
If a home or substantial portion of a home existed on January 1 but was not reflected correctly in the appraisal records, the appraisal district may later determine that an improvement was omitted.
The construction status on January 1 of each affected year matters. A property owner should not automatically assume that the value of a fully completed house can simply be applied to an earlier year when the structure was incomplete.
A Swimming Pool
A permanent swimming pool can increase a property’s market value and may be treated as an improvement for appraisal purposes.
If the pool existed during a prior tax year but was not reflected in the appraisal district’s records, the district may later review whether an omitted improvement should be added.
A Detached Garage, Workshop, or Shed
Detached structures can also affect property value.
Whether a shed or other structure materially affects the appraisal may depend on factors such as its size, construction, permanence, use, condition, and contribution to the property’s market value.
A Home Addition
An additional bedroom, expanded living area, second story, enclosed patio, or other substantial addition can change the characteristics and market value of a property.
If the appraisal records continued to show the property’s old square footage or improvement details, the appraisal district may later attempt to correct the records or add an omitted improvement.
Ordinary repairs and maintenance, however, are not treated the same way as new improvements.
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What If the Pool, Shed, or Addition Was Built After January 1?
This is an important distinction.
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Texas property is generally appraised at its market value as of January 1 of each tax year.
For example, if a swimming pool was completed in July 2026, the fact that it does not appear in the property’s January 1, 2026 appraisal does not by itself mean the pool was omitted from the 2026 appraisal roll.
The improvement did not yet exist in its completed form on the appraisal date.
If construction was already underway on January 1, however, the property’s actual condition on that date may become important.
Construction contracts, building permits, inspection records, dated photographs, completion dates, and other records can help establish what existed during the tax year in question.
Before accepting a prior-year omitted-property assessment, compare the appraisal district’s claimed value with the actual condition of the property on January 1 of each affected year.
Omitted Property vs. a New Improvement: What Is the Difference?
These terms are related, but they are not necessarily interchangeable.
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A new improvement generally refers to an improvement that increases market value and was not included in the preceding year’s appraised value.
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Omitted property involves taxable property that the appraisal district says should have appeared on an appraisal roll but did not.
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For example, a swimming pool completed during 2026 may become a new improvement for a future appraisal.
But if the pool was completed years earlier and should have been included in prior appraisal records, the appraisal district may treat the issue as omitted property and potentially add prior-year values.
The dates matter.
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So do the property’s condition, construction records, permits, appraisal history, and what appeared in the appraisal district’s records during each affected year.
How Far Back Can a Texas Appraisal District Assess Omitted Property?
For real property, Texas Tax Code §25.21 generally allows the chief appraiser to add omitted property for any of the three preceding tax years.
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For personal property, the statute generally provides a two-year lookback.
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A homeowner receiving an omitted-property notice should immediately identify:
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Which tax years are being added
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What property or improvement the district claims was omitted
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The value assigned for each year
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Whether the improvement actually existed as described on January 1 of each year
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Whether part or all of the improvement was already reflected in prior appraisal records
Do not assume that because an improvement exists today, the same completed value necessarily applies to every prior tax year.
Does the 10% Homestead Cap Protect a New Pool or Addition?
Not necessarily.
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Texas’s residence-homestead appraisal limitation generally limits annual increases in appraised value, but the calculation separately accounts for the market value of qualifying new improvements.
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That means the homestead appraisal limitation does not necessarily prevent additional value attributable to a new improvement from being recognized.
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A homeowner may therefore see a substantial appraisal increase after adding a pool, expanding a house, or completing another significant improvement even when the property receives a homestead exemption.
What If the Appraisal District Already Knew About the Improvement?
This can matter.
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Texas law specifically addresses actual or constructive notice of an improvement when determining interest on certain back taxes.
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Under Texas Tax Code §26.09, a building permit issued by an appropriate governmental entity can constitute constructive notice of an improvement to the appraisal district.
Under certain circumstances, back taxes on an omitted real-property improvement may avoid interest when the land itself did not escape taxation, the appraisal district had actual or constructive notice of the improvement, and the back taxes are paid within the applicable statutory period.
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This is why building permits, inspection records, prior appraisal photographs, construction documents, and correspondence with the appraisal district may matter.
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A permit does not automatically eliminate the back taxes themselves. It may, however, affect the treatment of interest when the statutory requirements are satisfied.
How Long Do You Have to Protest an Omitted Property Notice?
This is one of the most important parts of an omitted-property case.
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The normal spring protest deadline is not necessarily the deadline that controls when omitted property is later added through supplemental appraisal records.
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Under Texas Tax Code §25.23, supplemental appraisal records are subject to protest and appeal. A property owner generally must file a notice of protest within 30 days after the required notice is delivered.
That means a property owner receiving an omitted-property notice in October, November, or another time of year should not automatically assume:
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“Protest season ended in May, so there is nothing I can do.”
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A supplemental notice can create a separate protest deadline.
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Thirty days can pass quickly while an owner is gathering construction records, permits, photographs, valuation evidence, and prior appraisal information.
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If the issue also involves incorrect square footage, ownership information, exemptions, duplicate accounts, or other appraisal-record errors, Texas property tax appraisal corrections may also be relevant.
Do Omitted-Property Back-Tax Bills Have the Normal January 31 Deadline?
Not always.
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Texas has special delinquency rules for certain tax bills involving property omitted from prior tax years.
The Texas Comptroller explains that a tax bill based on omitted property that was not taxed in a prior year generally becomes delinquent on the February 1 that occurs at least 180 days after the tax bill is mailed.
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That can be very different from the normal rule under which most annual property tax bills become delinquent on February 1.
The actual delinquency date printed on the bill should always be reviewed carefully.
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An omitted-property notice, supplemental appraisal notice, and back-tax bill can also involve different deadlines.
Do not assume one deadline controls every part of the matter.
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If a back-tax bill has already become delinquent or collection activity has started, a Texas delinquent property tax attorney can review the tax years, appraisal history, ownership, and procedural status.
What Should You Do After Receiving an Omitted Property Notice?
Start by determining exactly what changed.
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Compare the new notice with the appraisal district’s prior records and gather documents showing when the improvement was actually built, completed, or placed in service.
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Useful records may include:
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Construction contracts
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Building permits
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Certificates of occupancy
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Inspection records
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Dated photographs
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Surveys
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Closing documents
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Prior appraisal notices
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Property-record cards
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Prior protest records
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Evidence showing the condition of the improvement on January 1 of each affected year
Then review three separate questions.
Was the Property Actually Omitted?
The improvement may already have appeared somewhere in the appraisal records, may have been partially valued, or may not have existed in the form claimed during the tax year being assessed.
Is the Value Correct?
Even when an improvement was omitted, the value assigned to it can still be disputed.
Depending on the notice and deadline, a Texas property tax appraisal appeal may allow the owner to challenge the appraisal or other issues raised by the district.
Are the Correct Years Being Assessed?
The appraisal district must apply the law to the appropriate tax years.
Construction and completion dates can therefore be critical.
What If You Bought the Property After the Improvement Was Built?
Do not assume the issue disappears merely because a previous owner built the improvement.
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A later owner may first discover an omitted-property issue when appraisal records are updated or a supplemental bill appears.
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The ownership history, January 1 ownership dates, closing documents, appraisal records, and timing of the assessment should all be reviewed.
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This is particularly important when purchasing a property that has undergone substantial remodeling, additions, new construction, or other improvements that do not appear to match the appraisal district’s records.
Can You Challenge the Value of an Omitted Pool, House, Shed, or Addition?
Potentially, yes.
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An omitted-property dispute is not limited to arguing whether the improvement exists.
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Depending on the circumstances, a property owner may challenge issues including:
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Whether the property was actually omitted
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The tax years involved
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The property’s condition on January 1
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The market value assigned to the improvement
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Ownership or situs
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Duplicate assessment
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Incorrect square footage or property characteristics
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Whether the improvement had already been included in prior appraisal records
The appropriate procedure depends on what the appraisal district changed and when the notice was delivered.
Why This Matters in November 2026
Texas tax assessors generally begin mailing annual property tax bills by October 1 or as soon afterward as practical.
That means many property owners are now reviewing their 2026 values, exemptions, taxing units, and final tax amounts.
If you are also reviewing your 2026 Texas property tax bill, make sure the final value, exemptions, taxing units, prior-year balances, and payment deadline are correct.
This is also a time when discrepancies become easier to notice.
A homeowner may realize that the appraisal record does not show a pool or addition correctly. Another may receive a supplemental appraisal notice for an improvement that existed in an earlier year. Others may receive an unexpected bill involving back taxes.
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Those situations should not automatically be treated like an ordinary current-year tax bill.
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Omitted-property matters can involve separate appraisal years, protest deadlines, back-tax calculations, interest rules, and evidence about when an improvement actually existed.
Received an Omitted Property Notice in Texas?
If an appraisal district has added a house, pool, shed, addition, or other improvement to prior-year appraisal records, review the notice before the protest deadline passes.
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Michael Saegert is a Texas property tax attorney and former Harris County Appraisal District counsel who represents property owners in omitted-property disputes, appraisal corrections, appeals, litigation, and delinquent property tax matters.
Saegert Law has also handled matters involving multiple appraisals and omitted property. You can review representative Texas property tax results to learn more about the types of property tax matters the firm has handled.
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Saegert Law can review the appraisal history, notice, construction records, tax years, and valuation to help determine what options may be available.