Every couple of years, Colorado homeowners get a notice from the county assessor with a number that determines how much property tax you’ll pay for the next cycle. Most homeowners glance at it and file it. Some pay attention. And a smaller group — the ones who understand how the process works — sometimes appeal and save real money.
Here’s how to be in that third group.
How Colorado assessments work
Colorado reassesses residential property every two years. Your county assessor determines your home’s actual value as of a specific date (the appraisal date), then applies the state’s residential assessment rate to get the assessed value. Property tax is calculated from that assessed value plus your local mill levies.
The key phrase: "actual value as of the appraisal date." Not what your home is worth today. Not what you paid. The value the assessor believes your home was worth on a specific date.
What’s on your notice
- Prior actual value. What the assessor said your home was worth in the previous cycle.
- New actual value. The number for the new cycle. This is the one to focus on.
- Assessed value. New actual value times the residential assessment rate.
- Estimated property tax. Based on last year’s mill levies (which may change).
- Comparable sales used. Sometimes included, sometimes not. Always ask if it isn’t.
When to consider appealing
You should consider an appeal if:
- The assessed actual value is meaningfully higher than what you’d sell for. Not just "a bit higher" — meaningfully. Off by 8% or more is worth investigating.
- Comparable sales the assessor used aren’t actually comparable. Different square footage, different condition, different neighborhood, different date range.
- Your home has issues the assessor didn’t account for. Foundation problems, water damage, deferred maintenance, difficult site (steep slope, no view, road noise) — anything that would reduce actual market value.
- Recent sales in your neighborhood contradict the assessment. If three similar homes on your street sold below the assessed value in the relevant window, you have a case.
When appeal isn’t worth it
- You bought recently at or above the assessed value. Your purchase price is a strong data point against you.
- Your home has been meaningfully upgraded since assessment. New kitchen, addition, finished basement — these can push actual value up.
- The delta is small. A $10,000 difference in actual value equals a small change in your annual tax bill. The time to appeal may not be worth it.
The appeal process (Larimer and Weld)
Both Larimer and Weld counties follow the state process. Rough timeline:
- File within the deadline on your notice (usually a specific date in May or June).
- Provide evidence. Comparable sales, condition photos, appraisal reports, anything documenting why the assessment is off.
- Assessor reviews. They may agree, partially agree, or deny.
- If denied, next level. You can appeal to the County Board of Equalization, then to the state Board of Assessment Appeals, then to district court.
- Most appeals resolve at the first or second level.
How to build a strong case
The best appeals include three to five comparable sales from within a year of the appraisal date, in your neighborhood, with similar size and condition. Bonus points for photos of the comparable homes showing they’re superior to yours. Bonus points for a professional appraisal if the delta is big enough to justify the cost.
The weakest appeals are just "I don’t think my home is worth that much." You need evidence, not opinion.
The 2027 reassessment is coming
Colorado’s next major reassessment cycle affects homeowners in 2027. Values will move meaningfully in some Northern Colorado submarkets — Greeley and Wellington especially, where prices have appreciated faster than the region average. Prepare now: keep records of any condition issues, document deferred maintenance, and note any sales in your neighborhood that would support a lower value if your notice comes in high.
Where a Realtor can help
This is one of the more useful, less-known things a Realtor can help with. Pulling comparable sales, running a candid CMA against your assessment, and identifying whether the appeal is likely to succeed — that’s ten minutes of my day, and it can save you hundreds or thousands of dollars a year.
I don’t do this to sell you anything. I do it because it’s a small favor that pays back the trust.
How I’d want a homeowner to feel about assessments
Informed. Not intimidated. Aware that appeals are a legitimate part of the system, and that a strong case sometimes wins meaningful savings.
If you’d like me to look at your assessment against real comparable sales, I’m happy to. Bring the notice; I’ll bring the market read.