This commentary is by Kubs Lalchandani, who grew up and lives in Boulder. He is co-owner of Treeline Veterinary Cancer Care in the Table Mesa Shopping Center and a partner at Lalchandani Simon PL, a law firm.
In April 2024, a friend purchased a home in Boulder in a standard arm’s-length transaction. On May 1, 2025, he almost fell over when he received his 2025 Notice of Valuation from the Boulder County Assessor’s Office.
The county had increased his home’s value by more than 30% over what he paid. Nothing had changed about the home — no remodels, no market shifts and no new comps. Yet the assessed value — and his property tax bill — just jumped. This wasn’t an error in the system. It is the system.
Under Colorado law, assessors are required to use a mass appraisal model that ignores the most obvious and reliable indicator of a property’s worth: an actual fair market sale transaction. Specifically, C.R.S. § 39-1-103(5)(a) mandates that residential property be valued “solely by consideration of the market approach to appraisal.”
But in practice, this “market approach” doesn’t consider your individual purchase. Instead, assessors use “comparable” sales that occurred between January 1, 2023, and June 30, 2024, regardless of whether they reflect the actual sale price of a home. Moreover, C.R.S. § 39-1-103(8)(a) requires assessors to use a “representative body of sales… sufficient to set a pattern,” meaning that subjective calculations — not reality — dictate a property’s assessed value. This system may disregard the best evidence of all: what a buyer was willing to pay in a competitive market.
When determining property value for a loan, an estate or a court case, a recent sale is considered the gold standard. And in many other states, a recent arm’s-length sale of a property reflects its presumptive value for tax purposes. Yet, Colorado law allows the assessor to ignore that transaction completely. This system undermines confidence in the fairness of the property tax system and hurts Boulder County residents already dealing with high costs.
The legislature should amend Colorado Revised Statutes § 39-1-103 to allow recent, arm’s length sales to serve as presumptive evidence of market value. That would ensure homeowners are taxed based on reality.
I agree with this in principle. If a home is sold more recently than the assessment period used, it would make sense to use the actual sale price.
The difficulty, though, in practice, is that trying to assess the rest of the homes that haven’t been sold, still need a better system than we have. Markets can change quickly. For instance, the current reality is that the market is softer than it was during the period the assessors are using. And it’s hard to find real comparables at any time, even in a community with seemingly similar houses.
Where I used to live in Jeffco, there were literally no comps most of the time for my trilevel when most homes in the immediate area were ranches that sold for more and were often flipped. I’d been in that house for decades without major remodeling.
The system this state uses needs an overhaul, I agree, but just picking out those that have sold recently is a narrow and time consuming piece of a puzzle that needs more complete change.
Completely agree. In fact, in their system of appraisals, you end up with a number of flaws: 1. recently sold homes have two values – the recently sold value and the appraised value 2. homes not in the recently sold period are valued based on the sold value, not the appraised value (which can differ markedly). 3. recently sold homes are appraised based on the recently sold home values of their neighbors – all pointing to each other – causing higher and lower pushes in the assessments than the difference in features because of the self-referential nature of the model. It is a completely flawed implementation of the software. It only works if you make the recently sold assessments = recently sold home values. How can we fix this?!