How to Appeal Your Property Tax in Colorado: Step-by-Step Guide

In Colorado you protest a real property value to the county assessor first. Starting with the 2027 notices, the protest must be delivered, postmarked or given in person by June 1 (C.R.S. § 39-5-122(2), as amended by Senate Bill 26-046, effective January 1, 2027). From August 10, 2022 through 2026 the date was June 8. A denied protest then goes to the county board of equalization.

That board is the second step, not the first. After it, you pick one of three routes: the state Board of Assessment Appeals, a new trial in district court, or binding arbitration. The last dates for the board and the final step both depend on whether your county runs Colorado’s “alternate protest and appeal procedure,” explained below.

Colorado protest and appeal deadlines

In the second year of a reassessment cycle, if your value did not change, the notice of valuation can come with your tax bill instead of a separate May mailing (§ 39-5-121(1.2)). The June protest date still applies.

Personal property follows its own dates in the same sections (June 30 for the protest under the text in force now). Everything on this page is about land and buildings.

What changed in 2022 and 2026

An older guide can be off by a week or more on these dates.

• Protest date. House Bill 22-1416 set June 8, effective August 10, 2022. SB 26-046 (Session Laws 2026, ch. 10, signed March 26, 2026) returns the real property date to June 1. That change takes effect January 1, 2027, per the history note to § 39-5-122. The notice text that takes effect the same day names June 1 as well (§ 39-5-121(1)(a)(I)).
• Last step after the county board. Until August 12, 2026, § 39-8-108(1) allowed an appeal “no later than thirty days after the date such denial was mailed.” Since August 12, 2026 (SB 26-046, § 16), the limit is the later of September 1 or, in an alternate-procedure county, December 1. The 30-day count survives only for a petitioner notified “outside of the regular notification schedule.”
• Arbitration notice. You notify the county board of equalization of your intent to arbitrate by the same September 1 or December 1 dates (§ 39-8-108.5(2)(a)). Off the regular schedule, the 30 days run from the board’s decision, not from the date it was mailed.

Which counties run the alternate procedure

Section 39-5-122.7 gives two routes. Any county may elect the alternate procedure at the assessor’s request, and must do so by May 1 of the year (subsection (1)). Counties with more than 300,000 people, by the state demographer’s latest published estimate, have had to use it “in any year of general reassessment” since January 1, 2024 (subsection (4)). Reassessment runs in two-year cycles counted from 1989 (§ 39-1-104(10.2)(a)).

We do not print a list of counties, because a county can opt in for any year. The assessor’s written denial comes on the form described in § 39-8-106. That form must tell you “the time and place at which the county board of equalization will hear appeals” and the filing date, and the county board’s decision must state “the time by which such appeal or submission to arbitration must be made” (§ 39-8-108(1)(b)). Go by the dates printed on those two documents.

Filing the protest with the assessor

The notice arrives with a form you can use, but it is not the only way in. You may appear in person, return that form, or send a letter “stating in general terms the reason for the objection and protest.” The statute adds that “The county shall not prescribe the written form of objection and protest to be used” (§ 39-5-122(2)).

Mail counts on the postmark date, and filings are “presumed to be on time unless the assessor can present evidence to show otherwise.” A change in the assessment rate is not grounds for a protest. You can protest in a year when your value did not change: the right applies “whether or not there has been a change in valuation of such property from the previous year” (§ 39-5-122(2)).

Ask the assessor in writing for the data behind your value. At the protest stage the assessor has seven working days to provide it (§ 39-5-121.5); before a county board hearing the limit is three working days (§ 39-8-107(3)). The assessor first tells you the estimated cost, and you pay it before the data is released.

At the county board of equalization

The petition to the board must name “the actual value of such real property, stated in terms of a specific dollar amount, which is being offered as the correct valuation” (§ 39-8-106(1.5)). The board hears both sides “with no presumption in favor of any pending valuation” (§ 39-8-107(1)(a)). The same rule holds in every later appeal or arbitration (§ 39-8-108(6)).

A protest does not freeze your value in place. The Colorado Supreme Court read § 39-5-122(2) to let an assessor raise a value after a taxpayer protests: San Miguel County Bd. of Equaliz. v. Telluride Co., 947 P.2d 1381 (Colo. 1997). On appeal past the county board, the value “may not be adjusted to a value of more than five percent above the valuation set by the county board,” with an exception in § 39-5-125 (§ 39-8-108(5)(a.5), added by HB 22-1416).

After the county board: BAA, district court or arbitration

Board of Assessment Appeals. The BAA takes petitions online through its case system. Under § 39-2-125(1)(h), a taxpayer filing pro se pays no fee for the first two requests in a fiscal year, then $33.75 per parcel. An agent or attorney pays $101.25 per parcel. The BAA’s filing page says you may not file with it unless you have “filed an appeal with both your County Assessor and your County Board of Equalization.” By statute, the BAA hearing is “the last hearing at which testimony, exhibits, or any other type of evidence may be introduced,” and any review by the Court of Appeals rests on that record (§§ 39-8-107(1)(b)(II), 39-8-108(2)).

District court. Here you get a “trial de novo” in the district court of the county where the property sits (§ 39-8-108(1)(a)).

Arbitration. The arbitrator comes from a list kept by the county clerk and recorder, and the hearing is held within 60 days of selection (§ 39-8-108.5(1)(a), (3)(a)). For residential real property the arbitrator’s fees and expenses “shall not exceed one hundred fifty dollars per case,” and the decision says who pays them (§ 39-8-108.5(5)). The decision “shall be final and not subject to review” (§ 39-8-108(4)).

Missed the protest date: abatement

The notice itself warns that after the protest date “the taxpayer’s right to object and protest the adjustment in valuation is lost” (§ 39-5-121(1)(a)(I)). A separate remedy survives: a petition for abatement or refund of taxes “levied erroneously or illegally,” including for “overvaluation.” It must be filed “within two years after January 1 of the year following the year in which the taxes were levied” (§ 39-10-114(1)(a)(I)(A)). If you did protest and got a notice of determination, you cannot use abatement to claim overvaluation (§ 39-10-114(1)(a)(I)(D)).

More on Colorado property tax and nearby states

• Colorado property tax system explained
• Colorado homestead exemption
• Property tax calculator
• Moving to Aurora, CO in 2026
• New Mexico appeal guide, Kansas, Utah, Wyoming, Nebraska

Sources: Colorado Revised Statutes 2026, Title 39; SB 26-046; Board of Assessment Appeals filing fees.

Colorado protest questions

My notice says June 8, but a friend says June 1. Who is right?

Both, for different years. June 8 is the text in force through December 31, 2026. June 1 applies under the version of § 39-5-122(2) effective January 1, 2027. Your notice must print the deadline (§ 39-5-121(1)(a)(I)); if it ever differs from the statute, file by the earlier date.

I live in a big Front Range county. Do I get more time?

Not for the protest itself; June 1 (from 2027; it was June 8 through 2026) applies in every county. In a county on the alternate procedure, the later steps move: the assessor answers by August 15, the county board petition is due September 15, and the final appeal by December 1 (§§ 39-5-122(2), 39-8-106(1)(a), 39-8-108(1)(a)).

Can the value go up because I protested?

Yes, it can. The assessor may raise a protested value (Telluride Co., 947 P.2d 1381), and on appeal past the county board the value can end up as much as 5% above the board’s figure (§ 39-8-108(5)(a.5)).

Is it free to take my case to the BAA?

For your first two petitions in a July-to-June fiscal year, filing without an agent or lawyer, yes. After that it is $33.75 per parcel, and $101.25 per parcel if an agent or attorney files (§ 39-2-125(1)(h)).

If I choose arbitration and lose, can I still go to court?

No. An arbitration decision “shall be final and not subject to review” (§ 39-8-108(4)).