Visit the Boulder County Ballot Measures website for information about 2025 ballot measures.

Share your feedback on Boulder County’s website by Friday, Oct. 3. Take the website survey.

Assessor’s Office
Boulder Valley farmland landscape, with mountains to the right

Assessor's Office

Residential comparable sales for appeals

Interested in finding comparable sales of properties so that you may file an appeal? Use the Residential Comparable Sales lookup tool. If you need help, instructions and assistance are available on the Residential Sales page.

News and Information

2025 Property Value Appeal Notices of Determination

The Assessor’s Office mailed Notices of Determination to property owners who filed on-time appeals of their 2025 property value. The deadline to appeal determinations for 2025 to the Board of Equalization has passed.

Property owners who wish to contest their 2025 value may petition for abatement starting on the first working day of January within two years of the date the taxes were levied (Jan. 1).

Assessor Overview

The Assessor’s Office establishes values every two years for more than 120,000 properties within Boulder County, worth more than $120 billion in market value, using tools such as geographic information systems (GIS) and mass appraisal techniques to perform the appraisal analysis. Property values are used to set tax amounts which the Treasurer’s Office administers and collects.

Connect With Us

Services and Information

Contact Us

Assessor

Phone: 303-441-3530
Fax: 303-441-4996

Email

Mailing Address

PO Box 471
Boulder, CO 80306-0471

Hours: 7:30 a.m. to 5 p.m.
Monday-Thursday
Closed Friday

Locations

Assessor Boulder and Longmont Drop Boxes

Boulder

1325 Pearl St., 2nd floor
Boulder, CO 80302
Hours: 7:30 a.m. to 5 p.m.
Monday-Thursday
Map and Directions Boulder Location

Longmont

515 Coffman St., Suite 114
Hours: 7:30 a.m. to 5 p.m.
Monday only
Map and Directions Longmont Location

Lafayette

1755 S Public Road
Hours: 7:30 a.m. to 5 p.m.
Tuesday only
Map and Directions Lafayette Location