How to Appeal Your Property Taxes in Colorado: The Complete Homeowner's Guide

Most Colorado homeowners never question the value their county puts on their home — they just pay the bill. But that value is an estimate produced by a mass-appraisal model, and when it's too high, you're quietly overpaying every single year. The good news: Colorado gives every property owner a legal right to protest, the process is free, and you don't need a lawyer. Here's exactly how it works.

Start with your Notice of Valuation

Colorado reassesses property on a two-year cycle, in odd-numbered years. In a reassessment year, your county assessor mails a Notice of Valuation (NOV) around the start of May. It states the county's new "actual value" for your home — the number every tax bill for the next two years is built on. Even in non-reassessment years you can protest if something about your property changed or the record is wrong. The state's official overview of the system lives at the Colorado Division of Property Taxation, and the underlying law is Title 39 of the Colorado Revised Statutes.

Step 1 — Check the county's data on your home

Every assessor publishes the property record they used: square footage, bedrooms, bathrooms, year built, condition, lot characteristics. Pull yours up on your county assessor's site — for example Denver, Jefferson County, or Boulder County — and read it line by line (our county guides link every assessor we cover). Assessors value tens of thousands of homes with statistical models — errors are common, and a recorded extra bathroom or 300 phantom square feet directly inflates your value. See our guide to the signs your home is overassessed.

Step 2 — Compare against actual sales

Colorado law requires residential values to be based on the market approach: what comparable homes actually sold for during the statutory study period (an 18-month window ending June 30 of the year before reassessment). If similar homes near you sold for less than your assessed value during that window, you have the core of a winning case. Our evidence guide covers how to pick comps that hold up.

Step 3 — File your protest with the assessor

The first round is informal and free. You can typically protest online, by mail, by phone, or in person, and you'll state what you believe the value should be and why. The assessor reviews and mails a Notice of Determination — either an adjusted value or a denial. Counties accept protests during a short statutory window each spring, which is why services like ours prepare cases in advance and file the moment the window opens.

Step 4 — Escalate to the County Board of Equalization

If the assessor denies your protest or doesn't move enough, you can appeal to the County Board of Equalization (CBOE), which hears appeals in the summer. It's a short hearing — usually 10–20 minutes, in person or virtual — where you (or your agent) present evidence and the assessor defends the value. The board issues a written decision.

Step 5 — Further appeals (rarely needed)

• Binding arbitration — fast and informal; the arbitrator's decision is final.
• Board of Assessment Appeals (BAA) — a state-level administrative board under the Colorado Department of Local Affairs.
• District court — a full trial de novo; rarely worth it for a single residence.

The overwhelming majority of homeowner appeals are resolved at the assessor or CBOE stage, so don't let the longer ladder intimidate you.

What actually wins

• Comparable sales from the statutory study period that support a lower value
• Documented condition problems the model can't see — roof age, foundation issues, original kitchens and baths
• Errors in the county's property record (size, bath count, finished basement, quality grade)
• Lot-specific drawbacks: busy road, steep slope, easements, power lines

DIY or use a service?

You can absolutely do this yourself — this guide is the playbook. The trade-off is time: building a defensible comp set, writing the protest, and attending a CBOE hearing takes real hours, and weak evidence usually gets a form-letter denial. HomeTaxDrop does the whole thing for you — analysis, evidence, filing, and hearings — and you pay nothing unless your taxes actually drop. Check your home's numbers in 60 seconds to see if you have a case.

Frequently asked questions

Can my value go up because I protested?

Counties review the evidence you submit; a retaliatory increase out of the protest process is not how Colorado's system works in practice. The realistic downside of a weak protest is simply a denial.

Does a lower assessment hurt my resale value?

No. Buyers and their lenders price your home off the market, not the assessor's number. If anything, lower taxes make your home more affordable to a buyer.

What if I miss this year's window?

Sign up anyway. Values carry across the two-year cycle, the next window always comes, and preparing early means your evidence is ready on day one — which is exactly how we run appeals at HomeTaxDrop.