Appeal guide · Colorado
How to appeal a commercial assessment in City and County of Denver
7 steps from the notice to the Denver County Board of Equalization and beyond, with the forms, exchange deadlines and mistakes that decide commercial cases here.
Deadline
Protest to the Assessor delivered, postmarked or given in person by June 8 (C.R.S. 39-5-122(2)). Appeal to the County Board of Equalization by July 15, or by September 15 when the county uses the alternate protest and appeal procedure, which is required in reappraisal years for counties over 300,000 population, including Denver
Where to file
Assessor's online protest filing or the paper protest form returned by mail or in person; County Board of Equalization petitions filed with the Board at 201 W. Colfax Ave., Dept. 406
Statute
C.R.S. 39-5-122 (protest to the Assessor); C.R.S. 39-5-122.7 (alternate procedure); C.R.S. 39-8-106 and 39-8-107 (County Board of Equalization); C.R.S. 39-8-108 (further appeal)
The process, in order
The Assessor reviews protests on the written record and mails a notice of determination. At the County Board of Equalization, petitions may be heard by referees appointed under C.R.S. 39-8-102 who make recommendations to the Board, and hearings run as a short presentation by the petitioner and the Assessor's appraiser. The Board must decide by August 5 under the standard schedule or November 1 under the alternate procedure.
Forms you will need
- +Real Property Protest Form
- +Petition to the County Board of Equalization
- +Petition for Abatement or Refund of Taxes
- 1
Mailed by May 1 in reappraisal years
Read the notice of valuation
Confirm the actual value, classification, building area and the appraisal date. In the intervening year a notice is sent only if the value changed, but a protest is still allowed.
- 2
May to early June
Build the appraisal-date case
Prepare an income approach and sales comparison at June 30 of the prior year, using sales from the data collection period and market rent and vacancy at that date.
- 3
By June 8
File the protest with the Assessor
File online or with the paper protest form, attaching the operating statement and a rent roll as of the appraisal date for leased commercial property.
- 4
By July 15 in reappraisal years
Provide income data under the alternate procedure
Submit two full years of rental income, tenant reimbursements, itemized expenses and rent roll data to the Assessor so the requirement does not arise again later.
- 5
Last working day of June, or August 15 under the alternate procedure
Review the notice of determination
Compare the Assessor's determination with the indicated value and decide whether to petition the County Board.
- 6
By July 15, or September 15 under the alternate procedure
Petition the County Board of Equalization
File the petition with the Denver County Board of Equalization and prepare for a referee hearing. The Board must decide by August 5, or November 1 under the alternate procedure.
- 7
Within 30 days of the Board's decision being mailed
Choose the next forum
Appeal to the Board of Assessment Appeals, file in Denver District Court for a trial de novo, or submit to binding arbitration, whose decision is final.
Mistakes that lose City and County of Denver appeals
- Arguing current market conditions instead of value at the June 30 appraisal date.
- Using sales from outside the data collection period without justifying the extension or time adjustment.
- Missing the July 15 income data deadline under the alternate procedure, or ignoring the 90-day data requirement at the Board of Assessment Appeals.
- Assuming the July 15 County Board deadline in a reappraisal year when the alternate September 15 deadline applies, or the reverse in an intervening year.
- Relying on an abatement petition for a year in which a protest was already filed and decided.
Evidence rules
- 1.C.R.S. 39-5-122(2.5): under the alternate procedure, owners of rent-producing commercial property must give the Assessor two full years of rental income, tenant reimbursements, itemized expenses and rent roll data by July 15.
- 2.C.R.S. 39-8-107(5): an owner who appeals to the Board of Assessment Appeals must provide the same income, reimbursement, expense and rent roll data within 90 days unless it was already given to the Assessor; the county can move to compel and the Board can dismiss for noncompliance.
- 3.Sales evidence must come from the data collection period ending June 30 of the year before the reappraisal year, time-adjusted to the appraisal date; post-appraisal-date sales are not used.
- 4.Income and expense information provided on appeal is held confidential and may be shared only with the Assessor, the boards and the appraisers involved in the appeal.
Frequently asked
Can I protest in 2026 if Denver did not reappraise?
Yes. Owners can protest in the intervening year even without a new notice. The value still reflects the June 30, 2024 appraisal date, so the evidence must address value at that date.
What is the commercial assessment rate in Denver for 2026?
25% of actual value for commercial property, down from 27% in 2025. Most other nonresidential property is at 26% and vacant land at 27.5%.
What are my options after the County Board of Equalization?
Within 30 days of the decision being mailed, appeal to the Colorado Board of Assessment Appeals, file for a trial de novo in Denver District Court, or submit the case to binding arbitration under C.R.S. 39-8-108.
Does Denver require income and expense data?
Under the alternate procedure, rent-producing commercial property must provide two full years of income, reimbursements, expenses and rent roll data to the Assessor by July 15. A Board of Assessment Appeals case requires the same data within 90 days unless it was already provided.
File a stronger City and County of Denver appeal this cycle.
ATALI ELECTRIC builds the income, sales and uniformity exhibits, fills the county forms and tracks every deadline.