Property Tax Protest · Colorado
Protest your property taxes
in Colorado.
Colorado revalues every odd-numbered year, and by law the comparable sales must come from a fixed base period ending June 30 of the preceding even year — so a 2027 value rests on sales through June 30, 2026, not on today’s market. Protests go first to the county assessor starting May 1 (online, by mail, or in person in most counties); if the assessor doesn’t move, you appeal to the County Board of Equalization, and beyond that to arbitration, district court, or the state Board of Assessment Appeals. Because the statute fixes the appraisal date, the strongest evidence is a licensed appraisal tied to that exact date, built from sales inside the statutory study period.
The protest window opens May 1, when Notices of Valuation mail, and closes in early June — the exact last day is printed on your notice.
In the even (intervening) year values generally carry over unless the property changed, so the odd-year protest is the main event. Several large counties use an alternate protest calendar with later dates — one more reason the notice, not a blog post, is your authority.
The evidence
Boards act on value,
not frustration.
However Colorado labels the process, the case underneath is identical: show what your home was actually worth on the assessment date. A licensed, USPAP-compliant appraisal — comparable sales, documented adjustments, a signed opinion of value — is that showing. Start with the $5 check to see if the numbers are on your side before you spend real money.
- Valued as of your assessment date — not today
- Comparable sales with adjustments and citations
- Signed by a state-licensed CO appraiser
- Phone walkthrough — no stranger in your home
- Delivered in 48–72 hours, rush available
Colorado counties
Colorado questions
The window opens May 1, when the Notice of Valuation arrives, and runs into early June — your notice states the postmark deadline. If you miss it, Colorado allows a later abatement petition, but the protest window is the designed path.
Colorado statute fixes the appraisal date at June 30 of the even year before the reassessment, and boards can only weigh sales from the statutory base period. An appraisal prepared for a Colorado protest is written “as of” that date for exactly this reason.
We’re not an AVM, a computer model, or a real-estate agent estimate. Every report is prepared under the Uniform Standards of Professional Appraisal Practice (USPAP) and signed by a licensed appraiser in your state — the same qualification required for mortgage appraisals.