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Assessor’s Office

Assessor's Office

News & Information

Notices of Valuation to be mailed May 1

The Boulder County Assessor’s Office has completed its biennial reappraisal of all property in Boulder County. Notices of valuation are mailed to property owners on Saturday, May 1. For details and information, see: 2021 Reappraisal Announcement

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Property Value Appeals are accepted May 1 through June 1, 2021

Appeal Your Property Value

Business Personal Property

Assessor’s Office New Hours

4 day week calendarThe Assessor’s Office is one of several Boulder County departments participating in a pilot program to explore moving to a four-day work-week.

Starting January 4, the Assessor’s Office staff will be available Monday through Thursday, 7:30 a.m.–5:00 p.m. online and by phone, to take your questions or schedule appointments. Please call 720-574-1880, or email

Assessor’s Office Status

coronavirus imageAll Assessor’s Office locations (the main location in Boulder as well as remote offices in Longmont and Lafayette) are closed to walk-in traffic until further notice.

Staff are available online and by phone during regular business hours to take your questions or schedule appointments. Please call 303-441-3530, or email

Services & Information


The Assessor’s Office establishes values every two years for more than 120,000 properties within Boulder County, worth nearly $50 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.

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Contact Us

Due to COVID-19, all Assessors Office sites are closed for business until further notice. Please call or email us with your questions during our normal business hours.

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

Business Personal Property
Phone: 303-441-3316
Fax: 303-441-1783


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Mailing Address
Main: PO Box 471
Boulder, CO 80306-0471

1325 Pearl St., 2nd floor
Boulder, CO 80302
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Hours: 7:30 a.m.–5 p.m. M–Th

515 Coffman Street, Suite 114
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1376 Miners Dr., Unit 105
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