Denver County, Colorado Property Tax Appeal Guide for 2027

What deadline matters first

For Denver County’s regular 2027 real-property protest cycle, the first deadline to plan around is May 1, 2027 through June 8, 2027. Denver’s published protest window for the 2026 tax year was May 1, 2026 through June 8, 2026, and Denver’s FAQ describes a June 8 annual deadline for the current year, or the next business day if June 8 falls on a weekend or holiday. As of this analysis on 2026-06-21, the 2027 dates are projected from Denver’s annual window and should be checked against Denver’s 2027 form when released. Denver protest page Denver Assessment FAQ

Denver allows filing online, by mail, or in person during the protest window. The online filing starts by finding your property in Denver’s property system and using the Protest My Value tab. If you use paper, Denver’s 2026 form said all protests had to be received or postmarked by June 8, 2026, which is a useful reminder not to wait until the final evening. Denver protest page 2026 Property Value Protest Form

For a recent sense of volume, BusinessDen reported that Denver received 10,675 assessment appeals by the 2025 deadline, down from 24,956 appeals in 2023. That does not predict your result. It does show that many Denver owners use the protest process when they believe a value or classification is wrong. BusinessDen

A county-level tax estimate can help you decide how much time the protest is worth. The effective tax rate reference for Denver County is 0.47%, based on the Tax Foundation’s 2026 county table reporting Denver County’s 2024 median effective property tax rate. This is only a broad reference rate. Actual bills vary by assessment rate, mill levies, taxing districts, exemptions, and statutory changes. Tax Foundation

The common value appeal

Denver’s official value reason is Estimated value is too high. Denver explains this as providing market data to support a reduction in value. In plain English, this means you believe the Assessor’s actual value is higher than what similar homes supported for the required valuation period. Denver protest page

For the 2027 Colorado reappraisal, the appraisal date is June 30, 2026. Colorado defines the appraisal date as June 30 of even years and uses market data from at least 18 months and up to 60 months before that date. Denver has historically used a 24-month period ending June 30 for reappraisal, so this draft uses July 1, 2024 through June 30, 2026 as the likely Denver 2027 comparable-sale period. Colorado property tax terminology Denver Assessment FAQ

A good value protest usually does not argue that taxes are too high in general. It points to the assigned value and explains why similar sales support a different value. Denver’s form asks for your estimate of the property’s value and the basis for that estimate, including comparable sales, photos, rent roll, appraisal, or other supporting documentation. 2026 Property Value Protest Form

Other reasons you might appeal

Denver also lists official non-value reasons. Use the county’s labels exactly when they match your situation.

Incorrect property characteristics: This means the Assessor’s record describes your property incorrectly. Examples include square footage, condition, bath count, or use. If your home is listed with finished space it does not have, or a condition rating that does not reflect needed repairs, gather clear proof. Denver protest page

Incorrect property classification: This means the property is classified in a way that does not match its actual use. Denver states that the assessor is required to classify property based on actual use as of January 1 of every year. For 2027, that means actual use as of January 1, 2027. Denver protest page

These reasons can overlap with value, but they are not the same thing. For example, a wrong square footage entry may affect the value, while a wrong classification may affect the assessment rate used later in the tax calculation. State terminology explains that assessed value depends on market value multiplied by the assessment rate tied to classification. Colorado property tax terminology

If your Notice of Assessment says something else changed

A Notice of Assessment is the assessment notice that tells you what the county believes your property is worth or how it is assessed. In Colorado, the official label is Notice of Valuation, often shortened to NOV. The NOV lists the Assessor’s valuation, and Colorado says real-property NOVs are sent by May 1. Colorado property tax terminology

If your NOV shows a value change, start with Estimated value is too high if your concern is market value. If it shows a changed home fact, consider Incorrect property characteristics. If it shows a classification problem, consider Incorrect property classification. Use the official label that best matches the error you can prove.

Denver says a protest is an opportunity to show appraisal staff that the assigned value or classification is inaccurate. After you submit, Denver assigns the protest to appraisal staff, who review the information and make a determination to adjust the assigned value or classification, or deny the protest and retain the current value. Denver protest page

What evidence helps

The strongest evidence is usually simple, dated, and tied to the official issue. For value, focus on sales of similar properties in the immediate neighborhood during the likely 2027 Denver base period, July 1, 2024 through June 30, 2026. Denver’s 2026 form specifically asked whether similar properties sold in the immediate neighborhood within the base period. 2026 Property Value Protest Form

Choose comparable sales that are similar in location, property type, use, size, age, condition, quality, lot characteristics, and other value-related features. Colorado terminology defines comparable sales as similar property sales used for comparison in valuation. It also explains that sales data may be time-trended to the June 30 valuation date. Colorado property tax terminology

Colorado’s Assessors’ Reference Library says sales used in assessment work should be representative, comparable, screened, verified, and coded as typical sales. It also says only arm’s-length sales should be used for statistical measurement or to establish values, and that non-arm’s-length sales generally should not be used. Assessors’ Reference Library, Chapter 3

For property characteristics, use photos, contractor notes, floor plans, appraisals, prior permits, or other documents that show the record is wrong. Denver’s form allows supporting documentation such as comparable sales, photos, rent rolls, appraisals, and other information. Denver does not publish a numeric cap on comparable sales in the 2026 form, so quality matters more than volume. 2026 Property Value Protest Form

What the board can and cannot decide

The first review is with the Denver Assessor’s Office during the protest period. If a matter continues beyond the Assessor’s determination, the official county-level appeal body name to know is the Denver County Board of Equalization. Denver’s Board of Equalization appears on Denver’s Board instructions, and Colorado describes the County Board of Equalization as the county body that hears appeals from assessor determinations. Denver County Board of Equalization instructions Colorado Division of Property Taxation

The Assessor and board can review assessment issues such as value, classification, and facts that affect value. They cannot set the tax rate for every taxing district. Denver’s FAQ says the Assessment Division does not set property taxes or collect payments, and that mill rates are set by the various taxing authorities. Denver Assessment FAQ

This is why a lower value does not translate into a fixed dollar result until the rest of the tax calculation is known. Denver explains that taxes depend on actual value, assessment rates, and mill levies. Use the 0.47% effective tax rate only as a rough county reference, not as a promise or parcel-specific calculation. Denver Assessment FAQ Tax Foundation

If you disagree with a later board decision, Denver’s FAQ says instructions are included with the Board’s determination, and options may include the State Board of Assessment Appeals, District Court, or binding arbitration. Those are separate choices with their own rules and deadlines. Denver Assessment FAQ

How TaxSauce helps

TaxSauce helps you turn a confusing notice into a clear protest package. We help identify the official reason that fits your facts, organize comparable sales within the likely base period, and flag property-record items that may need documentation.

You stay in control. You review the evidence, choose the filing reason, decide whether the package is ready, and submit through Denver’s official filing options if you choose to proceed. TaxSauce does not promise savings, guarantee an outcome, or replace the county’s instructions.

For a Denver homeowner, the goal is a calm, evidence-based presentation. That usually means a short explanation, the right official label, and supporting documents that directly connect to value, classification, or property characteristics.