Colorado Property Tax

Colorado’s system turns on a chain most states do not use: actual value is what the assessor says the property is worth, the assessment rate set by the legislature turns that into assessed value, and the mill levy of each taxing district is applied to the assessed value. The rate is not a small technicality — residential property is assessed at a fraction of its actual value, and the rate itself is set fresh by the legislature, so the two numbers on your notice interact in a way few other states replicate.

In this section

• Actual value and the assessment rate — the multiplication that defines the Colorado tax base, why residential is valued by sales alone, and why the rate is legislative and volatile.
• The Notice of Valuation explained — what arrives by May 1, the two years of value it shows, and the odd-year revaluation cycle behind it.
• Protesting and the appeal path — the May 1 – June 8 protest window, the county board of equalization, and the three routes beyond it.
• Colorado property tax deadlines — the full calendar: NOV, protest, Notice of Determination, county board, and the payment dates.

Who does what

• The county assessor discovers, lists, classifies and values every property in the county. The assessor does not set tax rates and does not collect taxes.
• Taxing authorities — county, cities, school districts, special districts — set the mill levies each fall. School districts are levied separately from the other local governments.
• The county treasurer collects the tax. All property tax revenue stays within the county; property taxes fund no state services.
• The Division of Property Taxation (Department of Local Affairs) publishes the state’s procedures, calendars and the assessment-rate tables the assessors follow.

The odd-year reassessment cycle

Real property is revalued every odd-numbered year; personal property is valued annually. In even years, a real property’s value carries over from the last revaluation unless a change (construction, destruction, ownership use change) requires adjustment. For the 2025 and 2026 tax years, the comparable-sales window for residential valuation is January 1, 2023 through June 30, 2024 — market movements after that window are not, by themselves, evidence about the value set from it. The Notice of Valuation page explains what this means for reading your notice.

Protesting your value

If you disagree with the actual value or the classification, you may present oral or written objections to the county assessor during the protest period — May 1 through June 8 for real property. The assessor must decide your protest and mail you a Notice of Determination. Counties with populations over 300,000 are required to use an alternate protest schedule (later Notice of Determination, later county board hearings), and any county may elect it — the two schedules differ by roughly two months at every later step. The protest and appeal page walks the full ladder.

Finding your property: county search

Colorado has no single statewide property search — each county assessor runs its own. Denver’s official system, for example, searches assessment and tax data for real and business personal property by address, parcel ID or schedule number. Start from Denver’s official property search if that is your county, or find your county assessor through the Division’s official county-assessor directory. The state also maintains an interactive Property Tax Map of districts and rates — useful for exploring, but built on unaudited county-reported data, so treat your assessor as the authority for current figures.

Paying the bill

Tax bills reflecting the prior year’s taxes are mailed as soon as possible after January 1. Amounts above $25 may be paid in one payment by April 30 or in two halves: the first due by the last day of February, the second by June 15. Amounts of $25 or less are due in full by April 30.

What this does not cover

County-specific protest portals and local dates are not restated here — your assessor’s notice and site are authoritative for the adjusted dates the statute shifts. Senior and disabled veteran exemptions, and business personal property procedures, are outside this section. AssessCheck has no data connection to any Colorado county or the Division.