Colorado homeowners can protest their property value to the county assessor between May 1 and June 8, 2027, and 2027 matters more than most years because it’s a reappraisal year: the value you get will normally be used for both 2027 and 2028. Filing is free, you don’t need a lawyer, and if the assessor says no you can keep going. Here’s how it works.
1. Know how Colorado sets your value
Colorado reappraises real property every two years, in odd-numbered years. Your 2027 value is your home’s market value as of June 30, 2026.
Assessors build that value from sales before that date. The law starts with the 18 months up to June 30 and lets assessors reach back in six-month steps, up to five years, when there aren’t enough sales. In practice many metro assessors (Jefferson County, for example) use about 24 months: roughly July 2024 through June 2026. So the question isn’t what your home is worth today. It’s what it was worth in mid-2026, judged by sales from that period.
2. Read your Notice of Valuation
Assessors mail a Notice of Valuation (NOV) by May 1. In 2027, May 1 is a Saturday; the state notes statutory dates can shift for weekends, so your notice may arrive a little later. Many counties also post values online first.
Check:
- Actual value — the assessor’s market value as of June 30, 2026.
- Property facts — square footage, bedrooms and bathrooms, basement finish, lot size, year built. Mistakes here are easy to fix.
- Classification — your home should be classified as residential.
3. Decide whether you have a case
The strongest argument is market value: similar homes near you sold for less than your value during the data period. Look for sales between January 2025 and June 2026 that match your home’s size, age, style and location.
Condition also counts. The assessor usually hasn’t been inside. Photos of an original kitchen, an old roof or foundation problems, with contractor estimates, can support a lower value.
4. File your protest with the assessor by June 8
The protest window runs from May 1 to June 8. In 2027, June 8 is a Tuesday. Your protest must be delivered, postmarked or handed in by that date.
Depending on your county, you can file:
- Online, through the assessor’s appeal portal.
- On paper, using the form that comes with your NOV, or a letter.
- In person at the assessor’s office.
Give a specific value you think is right and attach your evidence. If someone else files for you, counties typically require a signed authorization — Adams County, for example, requires a notarized letter from the owner.
5. Watch for the Notice of Determination
The assessor reviews your protest and mails a Notice of Determination (NOD). When it arrives depends on your county:
- Standard schedule: by the last working day of June (June 30, 2027).
- Alternate schedule: by August 15. In 2027, August 15 is a Sunday.
Every county with more than 300,000 people must use the alternate schedule in a reappraisal year, and smaller counties can choose it. That means 2027 protests in the biggest metro counties run on the later timeline. Your NOV or the assessor’s website will say which schedule applies.
6. Appeal to the County Board of Equalization
If you disagree with the NOD, appeal to your County Board of Equalization (CBOE). The deadline is:
- July 15, 2027 on the standard schedule, or
- September 15, 2027 on the alternate schedule.
You usually file by completing the back of the NOD and sending it to the board, or online where your county allows it. State a dollar value. Hearings are short — in El Paso County each side gets 10 minutes — so bring a one-page summary, your comparable sales and your photos. The board must decide by August 5 (standard) or November 1 (alternate).
7. If you still disagree
Within 30 days of the CBOE’s decision, you can choose one of three paths:
- Board of Assessment Appeals (BAA) — a state board. Owners who file on their own pay no fee for their first two appeals in a fiscal year; represented taxpayers pay $101.25 per parcel.
- District court in your county.
- Binding arbitration, arranged through your county.
The CBOE decision explains how to file each one.
What the assessment rate means for your bill
Your tax isn’t charged on full market value. It’s charged on assessed value, which is market value times the assessment rate. For 2026, Colorado’s residential rates are 6.8% for local government levies and 7.05% for school district levies. HB24B-1001, passed in a 2024 special session, set those rates going forward, so they’re expected to apply in 2027 unless the Legislature changes them.
Because the rate is fixed by law, the only part of the bill you can fight is the value. Every $10,000 cut from your actual value removes $680 to $705 of assessed value, depending on the levy.
Seniors: check the homestead exemption
If you’re 65 or older on January 1 and have owned and lived in your home as your primary residence for at least 10 straight years, you may qualify for the senior exemption. It exempts 50% of the first $200,000 of your home’s actual value, when the state budget funds it. Apply with your assessor by July 15 (late applications are accepted through August 15). The exemption and a value protest are separate — you can do both.
Or let someone do it for you
You can do all of this yourself for free. If you’d rather not, a property tax consultant can file and argue the protest for you. Recoup Capital handles Colorado appeals for 30% of first-year savings, and you pay nothing if your taxes don’t go down.
Sources: Colorado Division of Property Taxation — Understanding property taxes in Colorado, DPT — Senior property tax exemption, C.R.S. 39-5-122, C.R.S. 39-5-122.7, C.R.S. 39-8-106, C.R.S. 39-1-104, HB24B-1001 fiscal note, DOLA — Appealing your residential property value, Board of Assessment Appeals — filing fees, Adams County Assessor — appeals process, Douglas County — appeal process in a reappraisal year, El Paso County — Board of Equalization appeal process.