How to Appeal Your Property Taxes in Colorado: A Homeowner’s Guide.

How to Appeal Your Property Taxes in Colorado: A Homeowner’s Guide

If you own a home in the Denver Metro or Front Range area, you know that property tax assessments have been a "hot button" issue lately. The 2025 reappraisal set values based on market conditions as of June 30, 2024, which flow into the next cycle. 2026 is an intervening year, and some owners won’t receive an NOV unless something changes.

The good news? You have the right to protest. Here is exactly how the process works and how a professional appraisal from VolkHaus can help.

1. Know the Deadline: Appeal Window is Generally May 1st to June 8th
In Colorado, County Assessors mail out Notices of Valuation (NOV) around May 1st. You have a very narrow window—typically until June 8th—to file a formal protest. If you miss the protest window, your options shrink dramatically and you may be limited to other remedies (like abatement/correction) that are narrower and harder. Always confirm your county's posted deadline for the current year. 

2. Understand the "Data Window"
This is where most homeowners get confused. For the 2026-2027 tax years, the County Assessor isn't looking at what your home is worth today. They are looking at a specific "Base Class" period that ended on June 30, 2024.

When you appeal, your evidence should focus on sales used for the county’s study period leading up to the June 30, 2024 appraisal date (the exact start date can vary by county and property type). Sales after June 30, 2024 usually carry less weight because they reflect a later market.

3. Mass Appraisal vs. Residential Appraisal
The county uses a "Mass Appraisal" system. This is a computer algorithm that looks at your neighborhood as a whole. It doesn't know that your neighbor's house was fully renovated while yours still has the original 1990s kitchen, or that your property backs up to a noisy road.

A professional appraiser does what the computer can't: * We physically (or virtually) inspect your specific property data.

• We select the most accurate comparables from the correct "Base Class" period.
• We deliver a defensible, well-supported appraisal aligned with the county’s valuation date and supported by market data.

4. How to File Your Protest
You can usually file your protest online through your county’s website (Denver, Jefferson, Adams, Boulder, etc.)  Along with your form, you should attach evidence. A "zestimate" is rarely accepted as evidence—but an independent appraisal report is the gold standard.

The Bottom Line
Don't wait until June 7th to start your research. If your Notice of Valuation seems high, reach out to an appraiser early to ensure the data supports a lower value. Contact us at 720-583-3200.