Buyers see a monthly payment estimate and assume the tax number is right. Often it isn't. Colorado property taxes come from a simple formula, but the inputs change by district, and two homes a mile apart can have very different bills. Here's how I explain the formula, where to find the real numbers, and what to watch at closing.
The short answer
The county assessor sets the home's actual value. That value times the residential assessment rate gives the assessed value. Assessed value times the mill levy, divided by 1,000, gives the tax. Mill levies stack up from the county, school district, city, and special districts like fire, water and metro districts. Colorado reappraises on a two-year cycle, and owners can protest the value. Taxes are paid in arrears, so they get prorated at closing.
Step by step
- Pull the last full-year bill. The county treasurer's website shows it. Use that, not the listing estimate.
- Find the tax district. The assessor's record lists the tax area. That tells you which mills apply.
- Check for metro districts. New-build communities often carry metro district mills for infrastructure debt. See HOA vs metro district.
- Explain the formula. Actual value × assessment rate = assessed value. Assessed value × mills ÷ 1,000 = tax.
- Check the current rate. The state changes residential assessment rates and adjustments by law. Look them up each year at the Colorado Division of Property Taxation.
- Watch reappraisal years. Counties mail notices of value in reappraisal years. Owners can protest by the deadline on the notice.
- Know about senior help. Colorado has a senior homestead exemption and a tax deferral program for qualifying owners. Rules apply. Point clients to the assessor.
- Read the proration. Colorado taxes are paid the year after they're assessed, so the seller usually credits the buyer at closing for their share of the current year. The contract sets how it's calculated.
A worked example (illustration only)
| Step | Number |
|---|---|
| Actual value | $500,000 |
| Assessment rate (example only) | 7% |
| Assessed value | $35,000 |
| Mill levy (example only) | 90 mills |
| Annual tax | $35,000 × 90 ÷ 1,000 = $3,150 |
Illustration only. The assessment rate and mills here are made up to show the math. Real rates change by law and by district. Confirm with the county assessor and treasurer.
How to explain it to your client
"Your property tax depends on three things: what the county says the house is worth, the state's assessment rate, and the local mill levy. Mills are set by the county, schools, city and special districts, and they're different block to block. I pulled the real tax bill for this house from the county, and I checked whether it's in a metro district. That's the number we'll use, not the estimate on the listing."
Watch-outs
- Listing estimates go stale. Always check the treasurer's site.
- New builds can jump. A new home may be taxed as vacant land the first year. The next bill can be much bigger.
- Metro districts. They can add a lot. Read the disclosure.
- Rules change often. Colorado has passed several property tax changes in recent years. Don't hard-code rates in your materials.
- Not tax advice. Send detailed questions to the assessor or a tax professional.
Further reading
- How property taxes work on Colorado mountain homes on coloradomountainhomefinder.com
- Arapahoe County property taxes by city on kennarealestate.com
This is training for real estate agents. It isn't legal or tax advice. Talk to a CPA or the county assessor. Check with your managing broker.
Questions
What is a mill levy?
One mill is $1 of tax for every $1,000 of assessed value.
How often does Colorado reassess homes?
On a two-year cycle. Check the county for the current notice schedule.
Can my client protest their value?
Yes, by the deadline on the notice of value, through the county assessor.
Why does the seller credit the buyer for taxes at closing?
Colorado taxes are paid in arrears, so the seller owes their share of the current year.
Are there tax breaks for seniors?
Colorado has a senior homestead exemption and a deferral program. Rules and eligibility apply.
Brian Lee Burke is the founder of PadLeaders, a Colorado real estate broker licensed since 2003, team leader of The Kenna Group at Keller Williams DTC (formerly Kenna Real Estate Group) and the author of Mastering Real Estate and The Real Estate Playbook. More about Brian.