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How to appeal your property tax assessment in Colorado

In Colorado, if the value on your notice is too high, you can ask to have it lowered. You don't need a lawyer.

Checked against official sources: Oct 21, 2026

Can I still appeal?

Closed for 2026 — opens by May 1, 2027

The 2026 protest window closed June 8, 2026 (county board appeals closed July 15, or September 15 in counties on the alternate schedule). The next window opens when 2027 reappraisal notices go out by May 1, 2027, and runs through June 8, 2027. In counties on the alternate schedule, county board decisions can come out as late as November 1, 2026; you then have 30 days from the mailing date to appeal to the Board of Assessment Appeals, district court or arbitration. Owners who did not protest in 2026 may still be able to file an abatement petition.

Get your letter ↓ What you can do now ↓

0.48%Median effective tax rate
$2,602Median yearly tax on a home
June 8 (county assessor)Deadline to appeal
Protest to the county assessor, then appeal to the County Board of Equalization (CBOE)First level of appeal

Colorado homeowners pay a median of $2,602 a year in property tax, an effective rate of 0.48%, the 47th highest of the 51 states we cover.

Deadline: June 8 (county assessor)

Step 1 - protest to the county assessor from May 1 through June 8 (postmarked, delivered or in person; next business day if June 8 falls on a weekend or holiday). Step 2 - if the assessor denies you, appeal to the County Board of Equalization (a board that hears appeals and evens out values between homes) by July 15 (the assessor must mail its Notice of Determination by the last working day of June). Large counties use an 'alternate' schedule: counties with more than 300,000 people must use it in reappraisal years, and any county may choose it. Under it the assessor decides by August 15, your board appeal is due September 15, and the board decides by November 1. Examples: El Paso County announced that 2026 real property protests had to reach the assessor by June 8, 2026. In Jefferson County for 2025, protests ran May 1-June 8, determinations were mailed by August 15, and board appeals were due September 15.

The assessor mails a Notice of Valuation (NOV) by May 1. It shows last year's and this year's actual value and comes with a protest form. In an intervening year (like 2026), a county may mail a separate notice only to owners whose value changed, and count the tax bill as the notice for everyone else. You can protest even if your value did not change.

Missed the deadline? What you can do now

  • Check your notice for every exemption you qualify for (see the exemptions on this page). If one is missing, ask the office that sets your value. Exemptions have their own deadlines.
  • Set a reminder for April 2027, when the next notice usually arrives. Then check the value and the deadline right away. Add to my calendar

Find your Colorado county

Where you file depends on your county. Pick yours for the office contacts, local tax figures and a step-by-step guide.

How much could you save?

Enter the market value on your assessment notice and what you think the home would really sell for. We estimate the yearly saving if the board agrees with you.

Use the full market value, not the assessed value, if your notice shows both. The estimate uses your bill or your state's median effective tax rate.

Some states cap how fast the taxable value of a home can rise (California, Florida, Michigan and Texas homesteads, for example). If your taxable value is already held below market value by a cap, a lower market value may not lower this year's bill.

How to appeal in Colorado, step by step

  1. Understand your assessment

    Your county assessor values your home. In Denver and Broomfield, which are combined city-and-counties, it is the city and county assessor. If the assessor turns down your protest, you appeal to the County Board of Equalization, which in most counties is the board of county commissioners (often using hearing officers it appoints). Denver and Broomfield have their own city-and-county board. Homes are valued at actual (market) value using only the market (sales) approach. Values are based on sales from a set study period and are adjusted to a fixed appraisal date. For tax years 2025 and 2026 that date is June 30, 2024. Your home's physical condition is taken as of January 1. The taxable value is a percentage of actual value set by the state. For 2026 the residential rate is 6.80% for local governments (after a 10% reduction on up to the first $700,000 of value) and 7.05% for school districts. You cannot protest the assessment rate itself. Colorado revalues all real property every two years, in odd-numbered years (2025, 2027). The even year (2026) is an 'intervening year': values normally stay the same unless something changed, such as new construction or demolition. The 2027 reappraisal will use sales up to June 30, 2026.

  2. Check the record and talk to the assessor

    The protest to the assessor is the first step, and it is fairly informal. You can file it online in many counties, by mail, by email in some counties, or in person. Before you file, check your property details and the sales your county used. Many assessors post comparable-sales search tools. The assessor must give you the data used to value your home within three working days of a written request (a fee may apply).

  3. Gather your evidence

    What works in Colorado:

    • Sales of similar homes nearby during the study period
    • Your own purchase price if you bought in an arm's-length sale during the study period
    • An appraisal valuing the home as of June 30, 2024
    • Corrections to your property record: square footage
    • Photos and repair bids showing condition problems as of January 1
    More detail
    • Sales of similar homes nearby during the study period (for 2025-2026 values: sales from July 1, 2022 to June 30, 2024), adjusted for differences
    • Your own purchase price if you bought in an arm's-length sale during the study period
    • An appraisal valuing the home as of June 30, 2024 (for tax year 2026)
    • Corrections to your property record: square footage, finished basement, bathrooms, year built, quality
    • Photos and repair bids showing condition problems as of January 1

  4. File your appeal

    First level: Protest to the county assessor, then appeal to the County Board of Equalization (CBOE). Send the assessor your protest by June 8. Use the form that came with your notice, the county's online appeal, or any letter saying why the value is too high. Give your own estimate of value as of the appraisal date (June 30, 2024 for 2026) and attach support. The assessor mails a Notice of Determination. If you still disagree, appeal to the CBOE by July 15 (September 15 in alternate-schedule counties). The petition usually comes with the Notice of Determination. Your petition must state a specific dollar value. You get a hearing, often before a hearing officer, where you and the assessor present evidence. The board decides by August 5 (November 1 in alternate-schedule counties) and mails the decision within five business days. Cost: No fee to protest to the assessor or appeal to the county board.

  5. Prove your case at the hearing

    Bring copies of your evidence for each board member. Keep to the value of your home, not the size of the bill.

    More detail

    The assessor's value has no built-in presumption of being correct. The law says there is no presumption in favor of any pending valuation, and the assessor must back up the value at county board hearings. Still, as the one appealing, you must show the assessment is wrong (Board of Assessment Appeals v. Sampson, Colo. 2005). In practice, you need evidence of a lower market value as of the appraisal date.

  6. If you lose: Board of Assessment Appeals (BAA), district court, or binding arbitration

    30 days after the county board's decision is mailed. Choose one of three options. (1) The state Board of Assessment Appeals: file a petition online and upload the county board's decision. Do not file your evidence with the petition; exhibits are due four weeks before the hearing. Hearings are usually at least four months after the petition is accepted. Fee: none for your first two petitions in a fiscal year (July 1-June 30) if you represent yourself, then $33.75 each; $101.25 if an agent or attorney files. You can appeal a BAA decision to the Colorado Court of Appeals. (2) District court in your county, for a new trial. (3) Binding arbitration: tell the county board within 30 days and pick a certified or licensed appraiser from the county's list. For a home, the arbitrator's fees and expenses are capped at $150 per case. The decision is final, with no further appeal. At any of these three, the value can be raised as well as lowered, by up to 5% above the county board's value.

  7. After you win

    The lower value is used for that year's taxes. Colorado taxes are billed the following January, so a 2026 value change shows on the bill mailed in January 2027. In the intervening year, the reappraisal-year value normally carries over unless the property changed. If you already paid and win at the BAA or in court, the county refunds the difference with interest. The next reappraisal in 2027 sets a new value, so you may need to protest again.

Official forms

Real Property Protest Form (Division of Property Taxation standard form; your county's version comes with your Notice of Valuation)

Open the official form page

Boulder County 2026 Real Property Appeal Form (county example)

Open the official form page

Petition for Abatement or Refund of Taxes (one-year petition)

Open the official form page

Short Form: Property Tax Exemption for Seniors

Open the official form page

Veteran with a Disability Exemption Application

Open the official form page

Rules that are different in Colorado

  • The assessor deadline is June 8 for real property, and it is strict. If you miss it, you lose that year's protest. You may still be able to file an abatement petition.
  • You must go through the assessor and the county board before you can appeal to the BAA, district court or arbitration.
  • Counties with more than 300,000 people must use the later 'alternate' schedule in reappraisal years (assessor decision by August 15, board appeal by September 15). Smaller counties can choose it. Check your notice for your county's dates.
  • Your county board petition must name a specific dollar value you think is correct.
  • Changes in the state assessment rate are not grounds for a protest. Only value and classification are.
  • At the BAA, district court or arbitration, the value can go up, by as much as 5% above the county board's value (since HB 21-1083).
  • Arbitration is final, with no appeal.
  • If you file a protest about overvaluation and get a Notice of Determination, you cannot later file an abatement for overvaluation for that same year.
  • Abatement petitions can be filed up to two years after January 1 of the year after the taxes were levied.
  • HB 25-1324 (2025) made the deadlines clearer and moved the end of assessor hearings to June 8.
  • HB 24B-1001 and related 2024 laws reset residential assessment rates. In 2026 local governments use 6.80% (after a 10% reduction on up to $700,000 of value) and school districts use 7.05%.

Is your home assessed higher than similar homes?

Market value is the standard, but by law the assessor's values for similar property similarly situated are credible evidence in an appeal. You can show that comparable neighboring homes are valued lower, but it works best alongside sales evidence. This works only in limited cases. Run the numbers with our unequal assessment calculator.

Most wins start with a mistake in the assessor's record of your home. Check it line by line.

Record card checklist

Exemptions that lower your bill without an appeal

An exemption is separate from an appeal: you apply once and it cuts your taxable value every year. Check you have every one you qualify for.

Senior property tax exemption

For owners 65 or older on January 1 who have owned and lived in the home as their primary residence for at least 10 straight years (surviving spouses may qualify). It exempts 50% of the first $200,000 of actual value. Apply to the county assessor January 1 to July 15. Late filings accepted until August 15, but without appeal rights.

Official details

Senior primary residence classification (2025-2026)

A reduced-tax classification for seniors who got the senior exemption at a previous home in 2020 or later but no longer qualify for it at their current home. Apply January 1 to March 15 (late until July 15, without appeal rights).

Official details

Veteran with a disability and Gold Star spouse exemption

For honorably discharged veterans with a 100% permanent service-connected disability rating or individual unemployability, surviving spouses of veterans who already had the exemption, and Gold Star spouses. It exempts 50% of the first $200,000 of the home's actual value. Apply January 1 to July 1 (late until August 1, without appeal rights).

Official details

Do you need a lawyer or a tax consultant?

You can protest and appeal yourself. An agent can file for you with your written authorization; the standard protest form has an agent section. At the BAA, agents and attorneys pay a $101.25 fee per petition. Self-represented owners file their first two petitions each year free. Paid representatives who give value opinions may also be subject to Colorado's appraiser licensing rules.

Free property tax appeal letter

Fill in your details and download a written appeal statement as a PDF. Most boards also require their own appeal form: file the form and attach this letter and your evidence to it.

The 2026 deadline in Colorado has passed. We set this letter to the 2027 tax year: send it after your 2027 notice arrives.

About you

Where should the board send its decision?

The property

The year printed on your notice.

Who gets the letter
Your appeal
Reasons (tick all that apply)
Other formats

Sign the letter. Send it by certified mail with a return receipt, or file it online or in person, before your deadline. Keep a copy and your receipt.

RobinClaim is a free information site, not a law firm or appraiser. The letter is a template, not legal advice.

Colorado property tax appeal FAQ

What is the deadline to appeal property taxes in Colorado?

Step 1 - protest to the county assessor from May 1 through June 8 (postmarked, delivered or in person; next business day if June 8 falls on a weekend or holiday). Step 2 - if the assessor denies you, appeal to the County Board of Equalization by July 15 (the assessor must mail its Notice of Determination by the last working day of June). Large counties use an 'alternate' schedule: counties with more than 300,000 people must use it in reappraisal years, and any county may choose it. Under it the assessor decides by August 15, your board appeal is due September 15, and the board decides by November 1. Examples: El Paso County announced that 2026 real property protests had to reach the assessor by June 8, 2026. In Jefferson County for 2025, protests ran May 1-June 8, determinations were mailed by August 15, and board appeals were due September 15.

Where do I file a property tax appeal in Colorado?

First level of appeal in Colorado: Protest to the county assessor, then appeal to the County Board of Equalization (CBOE). Send the assessor your protest by June 8. Use the form that came with your notice, the county's online appeal, or any letter saying why the value is too high. Give your own estimate of value as of the appraisal date (June 30, 2024 for 2026) and attach support. The assessor mails a Notice of Determination. If you still disagree, appeal to the CBOE by July 15 (September 15 in alternate-schedule counties). The petition usually comes with the Notice of Determination. Your petition must state a specific dollar value. You get a hearing, often before a hearing officer, where you and the assessor present evidence. The board decides by August 5 (November 1 in alternate-schedule counties) and mails the decision within five business days.

How much does it cost to appeal in Colorado?

No fee to protest to the assessor or appeal to the county board.

Can I talk to the assessor before filing?

The protest to the assessor is the first step, and it is fairly informal. You can file it online in many counties, by mail, by email in some counties, or in person. Before you file, check your property details and the sales your county used. Many assessors post comparable-sales search tools. The assessor must give you the data used to value your home within three working days of a written request (a fee may apply).

What if the board turns me down?

Next level: Board of Assessment Appeals (BAA), district court, or binding arbitration. 30 days after the county board's decision is mailed. Choose one of three options. (1) The state Board of Assessment Appeals: file a petition online and upload the county board's decision. Do not file your evidence with the petition; exhibits are due four weeks before the hearing. Hearings are usually at least four months after the petition is accepted. Fee: none for your first two petitions in a fiscal year (July 1-June 30) if you represent yourself, then $33.75 each; $101.25 if an agent or attorney files. You can appeal a BAA decision to the Colorado Court of Appeals. (2) District court in your county, for a new trial. (3) Binding arbitration: tell the county board within 30 days and pick a certified or licensed appraiser from the county's list. For a home, the arbitrator's fees and expenses are capped at $150 per case. The decision is final, with no further appeal. At any of these three, the value can be raised as well as lowered, by up to 5% above the county board's value.

What happens if I win?

The lower value is used for that year's taxes. Colorado taxes are billed the following January, so a 2026 value change shows on the bill mailed in January 2027. In the intervening year, the reappraisal-year value normally carries over unless the property changed. If you already paid and win at the BAA or in court, the county refunds the difference with interest. The next reappraisal in 2027 sets a new value, so you may need to protest again.

Sources

Checked Oct 21, 2026 against official Colorado sources. Local deadlines and fees can differ; confirm with your assessor or board.

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