Collin County, TX property tax appeal guide for 2027

Collin County property owners protest appraisal-record disputes to the Collin Appraisal Review Board. For the 2027 tax year, the regular protest deadline is May 17, 2027, because Collin CAD’s published rule is May 15 or 30 days after the appraisal district mailed the Notice of Appraised Value, whichever is later, and May 15, 2027 falls on a Saturday. Late protests may be heard only for good cause and not after the ARB approves the appraisal records. Sources: Collin CAD ARB protest and roll certification cycle and Collin CAD property tax protest and appeal procedures.

Key 2027 dates

Item	Date or rule
Appraisal date	January 1, 2027
Real-property notice cycle	Generally begins around mid-April
Regular protest deadline	May 17, 2027
Preferred comparable-sale window	February 1, 2026 through January 31, 2027
Late protest limit	Good cause only, and not after ARB approval of the appraisal records

What you can protest

Collin County’s official process allows property owners to protest issues that apply to the appraisal records. The most common residential value issues are your property’s appraised (market) value and the unequal value of your property compared with other properties. Other listed grounds include your property’s inclusion on the appraisal records, exemptions, qualification for an agricultural or timber appraisal, taxing units, ownership, change of use of land receiving special appraisal, failure of the chief appraiser or appraisal review board (ARB) to send a required notice, circuit breaker limitation issues, historic-site value allocation issues, and any action taken by the Appraisal District (CAD) or ARB that applies to and adversely affects you. Source: Collin CAD property tax protest and appeal procedures.

For your property’s appraised (market) value, the question is whether the noticed value is above market value as of January 1, 2027. Collin CAD explains that residential appraisal is neighborhood-specific and uses generally accepted mass-appraisal methods, recent market data, comparable sales, listings, and property characteristics. Source: Collin CAD, How Is Your Property Appraised?.

For the unequal value of your property compared with other properties, compare your property with similar properties in the same Collin CAD neighborhood or most comparable market area. Collin ARB procedures require separate determinations for excessive appraisal and unequal appraisal, so the evidence should make clear which issue you are asking the ARB to decide. Source: Collin ARB hearing procedures.

Building a stronger comparable-sale set

For a 2027 market-value protest, start with verified, arm’s-length sales that bracket the January 1, 2027 appraisal date. Based on Collin CAD’s stated residential profile practice, the preferred sale window for this page is February 1, 2026 through January 31, 2027. Prefer sales closest to January 1 when the properties are otherwise similarly comparable. Source: Collin CAD 2025-2026 Reappraisal Plan.

Good comparable sales should be similar in location, property type, use, lot or site characteristics, building class, construction quality, square footage, condition, age or effective age, amenities, and other value-related traits. Collin CAD sources emphasize the same neighborhood or most comparable market area. No official Collin CAD source supplied for this page states a hard county-wide mileage radius, gross-living-area tolerance, lot-size tolerance, or maximum number of comparable sales the ARB will accept. TaxSauce may start with a narrow search and a manageable candidate set, but those are organization choices, not local legal limits.

Avoid relying on transactions that do not reflect the open market unless you clearly explain why they still reflect the relevant market. Separately flag foreclosure or REO sales, short sales, distressed sales, related-party sales, atypical seller types, and other non-arm’s-length transactions. Collin CAD’s reappraisal materials specifically track non-arm’s-length, foreclosure-process, bank-owned or REO, and short-sale activity. Source: Collin CAD 2025-2026 Reappraisal Plan.

Useful evidence to gather

Useful evidence may include closing statements, purchase contracts, listing documentation, condition-of-sale documents, independent fee appraisals, inspection reports, repair estimates, renovation or remodeling contracts, building plans, surveys, photographs, and comparable-property photographs. Collin ARB requests evidence in retainable formats, preferably PDF through the online appeals portal before the hearing. Collin CAD’s protest procedures say it does not accept audio or video files, external email links, or evidence on USB, CD, DVD, memory-card, or device media, and multiple files may not exceed 20 MB per property. Sources: Collin CAD appraisal and informal review cycle and Collin CAD property tax protest and appeal procedures.

Filing options

Collin ARB’s FAQ says a protest is sufficient if it is in writing and identifies the property, the protesting owner, and the protest reasons. The FAQ says the Notice of Protest form is recommended, and it advises owners to check all protest reasons that apply to preserve rights during the hearing. Source: Collin ARB FAQ.

Collin ARB’s FAQ says protests may be filed by mail, in person, drop-box, or through the appraisal district’s Online Appeals eFile site if eligible. It also says the ARB will not accept protests submitted by fax or email. Source: Collin ARB FAQ.

Hearing volume context

For volume context, Collin County reported that the Collin County ARB had over 45,000 hearings in 2024. That figure does not predict any individual result, but it shows why organized evidence, clear protest reasons, and early preparation matter. Source: Collin County ARB application notice.

Tax-rate context

The effective tax-rate figure used for this page is a county-only reference point, not a full tax-bill rate. The latest available Collin County tax-rate notice cited for this analysis lists the county-only no-new-revenue tax rate as $0.145881 per $100 of value, which converts to about 0.00145881. A homeowner’s actual tax bill may include city, school district, college, special district, and other taxing-unit rates, and the 2027 adopted rates were not available as of this analysis on 2026-06-20. Source: Collin County notice about 2025 tax rates.

How TaxSauce can help

TaxSauce can help you organize comparable sales, flag transaction issues, estimate a value range, assemble evidence, and prepare a protest packet for review. You choose the protest reasons, review the evidence, decide whether to submit, and file with the Collin Appraisal Review Board using an official filing option. TaxSauce does not promise a reduction, a hearing result, or that a filing will be accepted if it is late or incomplete.