2025 Property Values, Taxes, and Budgets

Three different Boulder County elected offices are involved in the calculation and collection of property taxes. The county calculates, collects, and distributes tax on behalf of 135 different taxing entities.

Every two years the Assessor’s Office is required by the State of Colorado to assess the value of all residential and commercial properties. The valuations are provided to property owners in May (2025) and the Certified Tax Roll is given to the Treasurer’s Office in January of the following year (2026).

The Treasurer’s Office uses the valuations to calculate property tax for each individual property based on the property’s location within municipal and special taxing district boundaries.

A property’s location determines which of the different mill levies will be used to calculate its property tax (examples include school districts, water districts, fire districts, etc.).

Boulder County itself receives about a quarter of the property tax collected. The Board of County Commissioners determines the county’s mill levy and state law limits the increase in revenue the county can collect from property tax for general operations to 5.5%.

Yes. Real property valuation appeals are accepted by state statute from May 1–June 9, 2025. Visit the Appeals website for details. The Assessor’s Office bilingual staff are available to help you in English and Spanish. Assistance in languages is available through phone interpretation.

Because of changes in state law the assessment rate for residential properties will not be determined until after August 25. Mill levies for 2025 will not be established until December of 2025. Both these pieces of information are essential for calculating taxes and will not be available when Notices of Valuation are mailed out on May 1. Visit the How Property Taxes Are Calculated website for more details about property tax calculation.

The Boulder County Assessor’s Office has a mapping tool that shows basic property data, including change in value and tax distribution at the account level. Please note that the estimated property tax is a rough estimate of taxes based solely on the projected assessment rate and 2024 mill levies and your current home value.

Your property tax notice will be mailed to you by the Treasurer’s Office in early 2026.

An enhanced Property Search website is being developed, which will include updated tax distribution mapping information to help property owners better understand the relationship between their property values and property tax. The enhanced Property Search website is planned for release before the Certified Tax Roll is given to the Treasurer’s Office in January 2026.

Visit the How Property Taxes Are Calculated website for more details about property tax calculation.

While the Board of County Commissioners determines the county’s mill levies (which are used to calculate the county’s share of tax revenue), their tax raising powers are governed by state law which limits the increase in revenue the county can collect from property tax for general operations to 5.5%. About a quarter of the collected property tax goes to Boulder County.

However, some special districts (e.g. school districts, water districts, fire districts, etc.) are not subject to the 5.5% limitation.

The Boulder County Treasurer can’t provide accurate tax estimates until all 135 taxing entities determine their mill levies and the Treasurer’s Office receives the Certified Tax Roll (January 2026).

Visit the How Property Taxes Are Calculated website for more details about property tax calculation.

State law limits the increase in revenue the county can collect from property tax for general operations to 5.5%. However, some special districts (e.g. school districts, water districts, fire districts, etc.) are not subject to the 5.5% limitation.

State law limits the increase in revenue the county can collect from property tax for general operations to 5.5%. However, some special districts (e.g. school districts, water districts, fire districts, etc.) are not subject to the 5.5% limitation.

Will Boulder County’s budget grow because of the new property values?

State law limits the annual increase in revenue the county can collect from property tax for general operations to 5.5%.

These revenues are used to provide the services county governments are required by state law to provide as well as those the Board of County Commissioners in consultation with heads of departments and other county elected officials determine are in the public interest. Visit the Your Taxes at Work website for more information about how the county uses tax revenue to deliver services and programs for county residents and businesses.

Through the county’s budget process, which begins in April, the county’s Office of Financial Management and the Board of County Commissioners determine the county’s budget and mill levy. The public are invited to share feedback with the board throughout the process by emailing commissioners@bouldercounty.org. The board hosts public meetings and a public hearing in the second half of the year and the final budget and mill levy is approved in December of each calendar year.

Sign up to receive Commissioners’ News to be kept informed of the budget process. Opportunities for public comment will also be shared on the county’s social media channels.

No. Although an $800,000 property in a Home Rule City (e.g. Boulder, Louisville, Longmont, etc.) may have a higher tax bill than an $800,000 property in unincorporated Boulder, the county’s budget receives the same amount of revenue from both properties.

Two properties with the same valuation may have different tax rates because they are in different tax districts. All taxes in a district are voter-approved. The county collects the tax for all of the districts and then distributes it to the taxing entities.

Visit the How Property Taxes Are Calculated website for more details about property tax calculation.

Tax notices are mailed by the Treasurer’s Office near the end of January (2026) to the owner of the property. Find out more on the Treasurer’s Office website.

No, property tax cannot be appealed. However, a property’s valuation (which is used to calculate tax) can be appealed during a valuation year. The 2025 appeals period is from May 1 to June 9. Visit the Appeals website for details. The Assessor’s Office bilingual staff are available to help you in English and Spanish. Assistance in languages is available through phone interpretation.

The Colorado Constitution establishes a partial property tax exemption for qualifying senior citizens, surviving spouses of senior citizens who previously qualified, and for Disabled Veterans. The deadline for 2025 applications is July 15. The Qualified Senior Primary Residence Classification allows senior exemption portability for 2025 and 2026; the deadline to apply is July. The discount will first appear on the tax bill sent in January 2026. Visit the Senior Exemption website for details.

Mobile Home Exemption – A mobile home with an actual value that is less than or equal to $28,000 is exempt from property tax. Visit the Mobile Home Exemption website for details.

Schools, charitable organizations, and churches are also exempt.

In some circumstances, property taxes can be deferred until the property is sold or passes into other ownership at which time they must be paid with interest. More information about deferring property taxes can be found on the property tax deferral program website.

The Colorado Constitution establishes a partial property tax exemption for qualifying senior citizens, surviving spouses of senior citizens who previously qualified, and for Disabled Veterans. The deadline for 2025 applications is July 15. The discount will first appear on the tax bill sent in January 2026. Visit the Senior Exemption website for details.

Mobile Home Exemption – A mobile home with an actual value that is less than or equal to $28,000 is exempt from property tax. Visit the Mobile Home Exemption website for details.