Assessor

Tax rates (mill levies) are determined by each taxing authority (County, Cities and Towns, School Districts, Fire Departments, Water and Sanitation Districts, and others) in the fall of each year. These authorities provide services to you and are listed on your annual tax notice.

Amendment I, the Tabor Amendment, was approved by the voters in 1992 and restricts the ability of taxing authorities to raise tax rates or revenue without voter approval. Some tax authorities have chosen to provide temporary tax credits, which allow the tax districts to maintain its official mill levy and not exceed revenue limits.

Additional revenue limitations for certain taxing authorities and school districts were enacted in 2025 through SB24-233 and HB24B-1001.

The TABOR Amendment restricts the total amount of revenue growth an individual taxing entity (a cemetery district, for example) is allowed each year. This is computed by each entity utilizing a formula that takes into account inflation, new construction in the taxing entity’s boundaries, and other factors. The Amendment does not restrict the amount that an individual’s taxes may change, nor does it place a specific percentage limitation on any individual’s tax change. The Amendment does state that mill levies cannot be raised by a taxing entity without an election, except for very special circumstances. It also specifies that improved residential property must be valued using the market approach to value only.

The differences in assessment rates between residential homes and other types of property began as a result of an amendment to the Colorado Constitution (known as the Gallagher Amendment) approved by the voters in 1982, which limited the residential share of the property taxes. Historically, the State Legislature adjusted the residential assessment rate each year to meet Gallagher statutory requirements. However, In 2020, Amendment B to the Colorado Constitution repealed the part of Gallagher that dictated how assessment rates were set.  The rates continue to be set by the legislature annually, but under different rules.   Rates cannot be increased without a vote of the people, but they can be decreased. 

Senate Bill 24-233 made a significant change to the residential assessment rate beginning in 2025.  In prior years, there was only one residential assessment rate used to determine the "taxable value" of a residential property.  Now, two different assessment rates are applied; one for the school district and one for all other taxing entities.  Under this bill, the school assessment rate will be maintained at a higher percentage than the all other local government rate.