Rate Breakdown

Property taxes in Boulder County are calculated by multiplying the assessed value (minus exemptions) by the total local millage rate.

How Property Tax Works in Boulder County

Boulder County assesses property value once a year, typically in early February, based on the market value as of January 1. The County Assessor’s Office uses a “fair market value” approach, incorporating recent sales, income, and cost‑approach methods to determine the taxable base. Once the assessed value is finalized, the tax bill is calculated by applying the combined millage rate—expressed as dollars per $1,000 of assessed value. For 2024, the overall millage rate hovers around 80 mills, but individual components (school district, city, fire protection, special districts, etc.) can vary. Your final tax amount equals:
Assessed Value ÷ 1,000 × Total Millage Rate.

Available Exemptions

Colorado law provides several exemptions that can lower your taxable amount. Eligibility is determined by the County Assessor and must be claimed on the appropriate forms.

• Homestead Exemption: Reduces the assessed value of a primary residence by $250,000, significantly decreasing the tax burden for most homeowners.
• Senior Citizen Exemption: Residents age 65 or older with qualifying income may receive an additional exemption of up to $10,000 of assessed value.
• Disability Exemption: Qualified persons with a permanent disability can claim a $10,000 assessed‑value exemption, similar to the senior exemption.
• Veteran Exemption: Honorably discharged veterans (and in some cases, their surviving spouses) may receive a $10,000 exemption on the assessed value of their primary residence.

Exemptions are applied before the millage rate is calculated, so they directly reduce the dollar amount of tax you owe.

Payment Schedule & Deadlines

Property taxes in Boulder County are payable in two installments. Understanding the schedule helps you avoid penalties.

• First Installment: Due **October 1** for the portion covering July 1 – December 31 of the tax year. Paying by this date secures a 25 % discount on the balance due.
• Second Installment: Due **January 1** for the portion covering January 1 – June 30 of the following year. This payment must be made in full to avoid interest.
• Late Payments: If a payment is missed, a 5 % penalty is assessed on the overdue amount, plus 1 % interest per month until paid.
• Electronic Options: The County offers an online portal for one‑time or recurring electronic payments, which automatically apply any early‑payment discounts.

Appealing Your Assessment

If you believe your property’s assessed value is inaccurate, Boulder County provides a formal appeals process.

• Step 1 – Review: Receive your assessment notice, then compare your property’s value to recent sales of similar homes in your neighborhood.
• Step 2 – File an Appeal: Submit a written appeal to the Boulder County Board of County Commissioners within 30 days of the notice date. Include supporting evidence such as appraisal reports, comparable sales data, and photographs.
• Step 3 – Hearing: A hearing is scheduled before the Assessor’s Board of Appeals. You may present your case in person or via video conference.
• Step 4 – Decision: The board issues a written decision, usually within 60 days of the hearing. If unsatisfied, you may further appeal to the Colorado Board of Assessment Appeals.

Staying organized, meeting deadlines, and providing clear, comparable data are key to a successful appeal.