Every property in Colorado is assigned an actual value by the county assessor. Residential property is assessed at the residential assessment rate set by the legislature (currently around 6.7%); commercial and other classes use higher rates. Tax bills equal assessed value × mill levy. If your actual value is too high, you may be overpaying.

Property owners can appeal their actual value by filing a protest with the county assessor by June 8 in odd-numbered reappraisal years. If the assessor doesn't adjust, you can appeal to the County Board of Equalization, then to the Board of Assessment Appeals (BAA), arbitration, or district court.

Filing a protest with the assessor and the County Board of Equalization is free. The Board of Assessment Appeals charges a small filing fee. Reappraisal happens every two years.

Colorado offers a Senior Homestead Exemption that excludes 50% of the first $200,000 of actual value for seniors 65+ who have owned their primary residence for 10+ consecutive years. A similar Disabled Veterans Exemption is available for veterans with a 100% permanent service-connected disability. TABOR limits tax-revenue growth without voter approval.