Property owners can review values, file appeals and get help in person, online or by mail.
Boulder County, Colo. – The Boulder County Assessor’s Office will accept appeals for real property valuations from May 1 through June 8, 2026. Property owners who believe their home or other real property was valued incorrectly or classified incorrectly have the right to appeal during this period.
“Reviewing your Notice of Valuation is an important step for every property owner,” said the assessor, Cynthia Braddock. “If you believe your value or classification is not accurate, we encourage you to contact our office and file an appeal during the appeal window. Our staff is here to help residents understand the process and the information used to value their property.”
Who can appeal
Property owners may appeal if they believe their property’s market value is too high or too low, or if there is an error in the property record or classification. Under state law, each property in the county is revalued in odd-numbered years, and property owners receive a Notice of Valuation around May 1.
If your property value did not change in the odd-numbered year, your tax bill served as your Notice of Valuation. Only properties with new ownership since tax bills were mailed or with changes in value will receive a Notice of Valuation this year.
What property owners should review
The Assessor’s Office encourages property owners to carefully review their Notice of Valuation and confirm that the listed property facts and characteristics are correct. The notice describes the property, shows the actual value for the prior and current year, and serves as the form used to submit an appeal to the Assessor.
For the 2026 valuation cycle, properties were compared to similar homes that sold during the 24-month period from July 1, 2022, through June 30, 2024. Property owners may also review the Assessor’s records for their property and compare them with similar properties.
How the appeal review works
When a property value is appealed, the assessor reviews the value using a methodology similar to an appraisal. This includes reviewing comparable sales and other supporting market data. Property owners may also provide information that supports their opinion of value.
How to file an appeal (starting May 1)
Real property appeals may be submitted to the Assessor’s Office in the following ways:
In-person help during the appeal period
To help residents during the appeal window, the Assessor’s Office will offer additional in-person support.
- The Boulder office will be open on Friday, May 1, and Friday, June 5, outside normal business hours to accommodate appeals.
- Staff will also be available in the Longmont office May 11–14, with commercial appraisers on hand May 14
- and in the Lafayette office, May 18–21, with commercial appraisers on hand on May 21.
Appeals must be received by the Assessor’s Office or postmarked by 11:59 p.m. on Monday, June 8, 2026. Deadlines are strictly enforced.
What happens next
After an appeal is reviewed, the Assessor’s Office will mail a Notice of Determination by Aug. 15, 2026. Property owners who disagree with that decision may file a written appeal with the County Board of Equalization by Sept. 15. Instructions for filing with the County Board of Equalization will be included with the notice of determination.
Important note about taxes
Taxes themselves cannot be appealed through the Assessor’s Office. However, some individuals may qualify for property tax relief, exemptions, or deferrals, and the Assessor’s Office can provide information about those programs.
Business personal property appeals
Appeals for business personal property values may be filed separately with the Assessor between June 15 and June 30.