The Protest and the Appeal Path

Colorado’s appeal structure starts with a protest — a conversation with the assessor, not yet a formal appeal — and then offers an unusual choice at the top of the ladder: after the county board, the owner picks among three different routes (arbitration, district court, or the state’s Board of Assessment Appeals) with real trade-offs in cost, formality, and record.

Step 1 — the protest (May 1 through June 8)

An owner who disagrees with the actual value or the classification presents oral or written objections to the county assessor during the protest period — May 1 through June 8 for real property. This is the cheapest, fastest step, and in revaluation years it is where most residential cases end: the assessor’s staff can correct characteristics or correct the value on the spot.

One structural fact to check first: counties with populations over 300,000 are required to use an alternate schedule, and any county may elect it. The alternate schedule moves every later step by roughly two months — the dates below are the standard schedule’s.

Step 2 — the Notice of Determination

The assessor must decide the protest and mail a Notice of Determination (NOD). On the standard schedule, the notice arrives in late June. This document — not the original NOV — starts the next deadline: the county-board appeal runs from its mailing.

Step 3 — the county board of equalization

If the NOD leaves you unsatisfied, you appeal to the county board of equalization (CBOE) — county commissioners or their appointees sitting as the appeal board:

• Standard schedule: the board sits from July 1, must conclude hearings and decide by August 5, and the owner is notified in writing within five business days of the decision.
• Alternate schedule (large counties): NOD by August 15, hearings from September 1, responses by November 1.

Step 4 — the choice: arbitration, district court, or the BAA

A CBOE decision can be appealed — within 30 days of the date the decision was mailed — to one of three bodies:

• An arbitrator — a paid, faster, record-limited route the owner pays for.
• The district court — the judicial route, formal and open-ended in cost, trying the value de novo.
• The Board of Assessment Appeals (BAA) — the state’s administrative appeal board in Denver; the route that stays inside the state’s system, at no filing cost, with a record the courts can later review.

What this tells you: the choice is about money and formality as much as about the value. For a residential-scale dispute, the BAA is the usual recommendation of practice; for large commercial values, arbitration and district court exist precisely because the stakes justify them.

What it does not tell you: the 30-day clock from the CBOE decision’s mailing date is unforgiving at every route — calendar it the day the decision arrives.

Worked example (illustrative)

Illustrative timeline on the standard schedule — your county’s published dates control.

1. May 3, 2027: NOV arrives showing $512,000 (a revaluation year).
2. May 20, 2027: written protest filed with comparable-sales evidence from the statutory window.
3. Late June 2027: NOD arrives — value held. The CBOE appeal window is open.
4. July 2027: CBOE hearing; decision mailed July 25 with the value reduced to $495,000.
5. By August 24, 2027 (30 days): petition to the BAA if the reduction is not enough — the administrative route, at no fee.

What this page does not cover

The BAA’s hearing procedures, arbitration rules, and district-court tax-appeal practice are outside this page. The Division’s protests-and-appeals and understanding-property-taxes pages cited below are the authorities for the ladder and both schedules.