In Colorado, all business property, real and personal, is assessed at 29 percent. Property tax mill levies in Castle Rock, without any special district taxes, sum to 66.632 (or 6.6632 percent, applied to assessed value). Property taxes pay for schools, library, county roads and other services. All of the revenue generated by property taxes stays within the county.
There are some special districts within Castle Rock. Current mill levies for any special district taxes can be looked up for any property via the Douglas County Assessor’s website. That same site provides an explanation of how to calculate assessed value and property tax. As a simple example, a commercial building that is not in a special district, has an actual value of $345,000, and has an assessed value of $100,000 (29 percent of its actual value), would pay $6,632.00 per year in property tax.