How to Appeal Your Denver Property Tax Assessment This Fall
BOE hearings are running now. The September 15 deadline is weeks away. Homeowners who bought at peak prices have more recourse than they realize.
BOE hearings are running now. The September 15 deadline is weeks away. Homeowners who bought at peak prices have more recourse than they realize.
If a Notice of Valuation landed in your mailbox this spring and you set it aside thinking it was just paperwork, read this before September 15. Denver County Board of Equalization hearings are running right now through fall 2025. Some homeowners who filed informal protests in May and June are getting decisions back that they don’t fully understand. Others — particularly buyers who closed on Denver homes in 2023 or 2024 at peak prices — are staring at their first reassessment notice with no idea that it’s an opening position, not a final bill.
The search results for “Denver property tax appeal” are dominated by law firm lead-gen pages with gated content, phone-call forms, and almost no plain information. Here is the plain information.
What Your Notice of Valuation Actually Means
The Notice of Valuation from the Denver Assessor’s office states two numbers that confuse most first-time recipients: actual value and assessed value.
Actual value is the assessor’s estimate of your property’s market value as of the statutory appraisal date for the 2025–2026 cycle. It’s a mass-appraisal model. Nobody walked through your home. The assessor’s office values residential properties in Denver County using sales data and neighborhood algorithms, which means it doesn’t know about your cracked foundation, your dated kitchen, or the fact that the comparable house two doors down sold $55,000 below the figure on your notice. That’s not a knock on the assessor’s office — mass appraisal at county scale is genuinely difficult — but it does mean the number has real margin for error.
Assessed value is what actually drives your tax bill. For residential properties in Colorado, it’s your actual value multiplied by the residential assessment rate — a figure set by the state legislature that has shifted repeatedly in recent years. Before 2020, the residential rate floated downward as property values rose, a mechanism built into the old Gallagher Amendment. Voters repealed Gallagher in November 2020 via Amendment B. Since then the rate is fixed by statute, meaning rising values translate directly into rising bills. If you bought before 2019 and your taxes have been climbing in ways that feel disconnected from anything you did, that’s why. Confirm the current rate with the Denver Assessor’s office or the Colorado Division of Property Taxation at dpt.colorado.gov — it has moved following SB 23-238 and the defeat of Proposition HH in November 2023.
The mill levy is set separately by your taxing jurisdictions — Denver Public Schools, the City and County, RTD, and others — and applied against your assessed value. The Denver Assessor’s property tax estimator at denvergov.org/assessor gives you the figure specific to your parcel.
The notice is the assessor’s opening position. Colorado law gives you a structured process to challenge it, and a meaningful percentage of homeowners who go through that process come out with a lower valuation. Most don’t bother. That’s exactly why showing up matters.
The Two-Stage Process and Where the Calendar Stands Right Now
Colorado’s protest system has two distinct stages. Most coverage — including much of what assessor’s offices publish — blurs them together, and homeowners miss deadlines or waste effort at the wrong stage.
Stage 1: Informal Protest to the Denver Assessor
The deadline for the 2025–2026 cycle was the first Monday of June 2025, per C.R.S. § 39-5-122. If you filed before that date, you received or will receive a Notice of Determination. The assessor is required to respond by August 15. If you missed the informal protest deadline, Stage 1 is closed for this cycle.
Stage 2: Denver Board of Equalization Appeal
If your informal protest came back unsatisfactory — the assessor didn’t reduce your value, or reduced it less than the evidence supports — you escalate to the Denver Board of Equalization. The BOE deadline is September 15, 2025, per C.R.S. § 39-8-106. This is where the cycle stands right now. Homeowners who filed timely informal protests and received decisions in June and July are in the window to file BOE appeals.
If you missed the informal protest window entirely and believe your property is seriously overvalued, consult a property tax attorney about whether any remedies remain for your situation. For everyone else who filed a timely protest and received a Notice of Determination they disagree with: file a BOE appeal before September 15. There are no extensions.
How to Pull Your Own Comparable Sales from the Denver Assessor Portal
This step is free. It takes under an hour. It uses the same category of data the assessor used to value your home.
Go to denvergov.org/assessor, select “Property Search,” and enter your address. Your property record shows your actual value, your property characteristics (square footage, bedrooms, year built, lot size), and a link to the comparable sales used to support your valuation.
Find the “Sales” or “Comparable Sales” tab. Colorado assessors are required by statute to use market sales data as the primary valuation method for residential property, from a statutory six-month window centered on the cycle’s appraisal date. Confirm the exact appraisal date for the 2025–2026 cycle with the Denver Assessor’s office at (720) 913-4162 — that date determines which sales are in scope.
Filter your comps to match your property on the characteristics that drive value: square footage (within roughly 10–15% of yours), year built, neighborhood, property type. Export or print the results. Calculate the median price per square foot from your filtered comps — not the average, which a few outlier sales can distort — then multiply by your home’s square footage. If that number sits well below your assessed actual value, you have a case.
A $40,000 gap on a mid-range Denver home is worth filing on. Larger gaps are stronger cases.
Here’s what that looks like concretely: if your home is a 1,450-square-foot brick bungalow in Sunnyside that the assessor has valued at $580,000, and six comparable brick bungalows in Sunnyside and West Highland sold during the relevant window at a median of $525,000, your argument is simple. The assessor’s model overshot by roughly $55,000. That’s not a complicated case. That’s a Tuesday afternoon and a printed spreadsheet.
One thing the comparable sales tool won’t capture: condition. Deferred maintenance, a non-conforming layout, a sloping foundation, a non-permitted addition — a buyer would discount for all of those, but the mass-appraisal model can’t see them. If your home has condition issues that affected its market value, document them with photos and contractor estimates. They’re relevant at a BOE hearing even when they don’t appear in the comp data. In our home & property coverage, we’ve covered related issues Denver homeowners often discover too late, including what inspectors flag most often before a sale.
What to Do If the Assessor’s Response Didn’t Help
If you filed a timely informal protest and received a Notice of Determination that left your value unchanged — or one that was vague enough to be useless — you have until September 15 to file a BOE appeal.
The Denver BOE appeal form is available through denvergov.org/assessor. You’ll need your schedule number (the parcel identifier on your Notice of Valuation), your contact information, the value you’re contesting, and the value you believe is correct. Attach your supporting documentation: the comp sales you pulled, photos, any independent appraisal you’ve obtained.
Filing online is faster. Filing by mail is also accepted, postmarked by September 15 — use certified mail with return receipt so you have proof of the postmark. Confirm the current mailing address with the assessor’s office before sending.
After September 15, your options move to the State Board of Assessment Appeals, district court, or binding arbitration. The State BAA is the most common next step. It involves more paperwork, longer timelines, and at that level most homeowners hire an attorney — which is fine, but also a good reason to resolve this now, at the stage you can handle yourself in a half-day.
What Actually Happens at a BOE Hearing
Most homeowners who picture a BOE hearing imagine a courtroom: a judge, rules of evidence, attorneys. It’s nothing like that. It’s closer to a business meeting, which is good news for anyone representing themselves.
Denver BOE hearings are conducted by contracted hearing officers — not elected officials, not judges. A typical hearing runs 15 to 30 minutes. No attorney required. No formal rules of evidence. The burden is on you to show that the assessor’s value is incorrect, but “showing” means presenting relevant comps and explaining discrepancies, not constructing a legal argument. If you’ve ever presented a budget to a skeptical manager, you’re overqualified for this.
The assessor’s representative presents their justification for the original valuation — usually a brief summary of the comps and methodology. You present your evidence. The hearing officer may ask questions. That’s it. No cross-examination in any meaningful sense.
Bring: printed comparable sales filtered and annotated with your notes; a one-page summary showing your median comp value versus the assessed value (make the math easy to follow); photos of condition issues if relevant; your Notice of Valuation and Notice of Determination; and any independent appraisal you’ve obtained — not required, but useful if you have one.
Confirm with the Denver BOE clerk — reachable through the assessor’s office — whether your hearing is in person, remote, or available in both formats.
The practical reality the assessor’s office won’t advertise: most valuation notices go completely uncontested. The homeowner who shows up with printed comps and a clear one-page summary is already in the minority that gets results. Hearing officers see dozens of cases a day. Organized documentation stands out because disorganized documentation — or no documentation at all — is the norm.
The Math: What a Successful Appeal Actually Saves You
The dollar value of a successful appeal depends on three things: how much you reduce your actual value, the current residential assessment rate, and your parcel’s specific mill levy. Confirm the current assessment rate at dpt.colorado.gov and your mill levy through the Denver Assessor’s property tax estimator before running your own numbers.
The calculation: take your reduction in actual value, multiply by the residential assessment rate to get the reduction in assessed value, then multiply by your mill levy (expressed as mills ÷ 1,000) to get annual tax savings. Multiply that by 2 for the full two-year cycle.
The savings scale significantly on higher-value properties. On homes above $700,000 where the assessor’s value appears to be off by 15% or more, a BOE hearing is straightforwardly worth the time. For mid-range homes with moderate discrepancies, I’d argue it’s still worth the half-day — but that’s a judgment call. What’s not a close call: if the gap is real and you’ve documented it, the effort is a few hours and the cost is zero.
Denver’s 2023 reassessment cycle saw residential values rise an average of roughly 33% countywide. The 2024 market was softer in many neighborhoods, so 2025–2026 increases are expected to be more modest — but call the assessor’s office at (720) 913-4162 for neighborhood-level figures. Their data is authoritative. Third-party estimates, including ones you’ll find in news coverage, are not. Denver homeowners who are also navigating age-related tax relief should separately review what a senior property tax exemption can save — it’s a different mechanism from the appeal process but can stack with a successful valuation reduction.
Hiring a Property Tax Protest Firm: Most People Reading This Shouldn’t
The Denver market has both locally focused Colorado practices and national tech-enabled platforms that operate here. The short version: for most mid-range Denver homeowners with a moderate discrepancy, doing it yourself is the better call. Pulling comps takes under an hour. A BOE hearing takes a half-day. If your annual tax savings from a successful appeal are modest, a firm’s contingency cut can leave you with little net benefit after fees.
The contingency model — no savings, no fee, but a percentage of first-year savings if it works — makes more sense on higher-value properties. Above $700,000 with an apparent overvaluation of 15% or more, the absolute dollar savings are larger and a professional presentation may be worth the contingency cost, particularly for someone with no time to prepare.
Before you hire anyone, ask four questions. What is the contingency rate and is there a flat filing fee on top of it? Do you attend the BOE hearing, or only handle the informal protest stage? Will you represent me through the State BAA if the BOE result is unsatisfactory? What’s your timeline and how do you communicate results? Some high-volume national platforms are efficient at informal protests and considerably less attentive once cases require real work. If any firm is vague on those four questions, keep looking.
If Your Address Says Denver But Your County Isn’t Denver
This section is for readers in Lakewood, Arvada, Aurora, Englewood, Centennial, and other municipalities who searched “Denver property tax appeal” and ended up here. The legal framework is identical — Colorado statutes govern the process statewide — but the offices, portals, and deadlines are county-specific. Filing with the wrong county doesn’t get forwarded. It just fails.
Jefferson County handles properties in Lakewood, Arvada, Wheat Ridge, and unincorporated Jeffco. Jefferson County Assessor: jeffco.us/1329/Assessor, (303) 271-8600. The BOE deadline is also September 15 by Colorado statute, but confirm current-year specifics on their site. Many Golden, Lakewood, and Arvada neighborhoods were up 30–40% in the 2023 cycle.
Arapahoe County handles Aurora (the eastern portion), Englewood, Centennial, Littleton, and Greenwood Village. Arapahoe County Assessor: arapahoegov.com, (303) 795-4600.
The Aurora split is genuinely confusing — some Aurora addresses are Denver County, others are Arapahoe. Don’t guess. Look at your Notice of Valuation. The issuing office is printed on the notice. That tells you which county’s BOE you file with. Go to that county assessor’s website for the correct forms, portal, and filing instructions.
Quick-Reference Checklist
Critical date: September 15, 2025. Statutory per C.R.S. § 39-8-106. No extensions.
Key contacts:
- Denver Assessor property search and BOE filing: denvergov.org/assessor; (720) 913-4162
- Jefferson County Assessor: jeffco.us/1329/Assessor; (303) 271-8600
- Arapahoe County Assessor: arapahoegov.com; (303) 795-4600
- Colorado Division of Property Taxation (assessment rate): dpt.colorado.gov
Before you file:
- Parcel/schedule number (on your Notice of Valuation)
- Notice of Determination from your informal protest
- Comparable sales pulled from the assessor portal, filtered to the statutory window around the appraisal date
- The value you’re contesting and the value you’re requesting
- Photos and condition documentation if relevant
At the hearing:
- Printed comps with your median calculation shown
- One-page summary: assessed value vs. comp-supported value
- Photos of condition issues
- Independent appraisal if you have one
The comp math: Pull filtered sales from denvergov.org/assessor — similar size, type, neighborhood, within the statutory window. Calculate median price per square foot. Multiply by your square footage. If the result is $40,000 or more below your assessed actual value, you have a case worth filing.
The window is open. Most people who have a valid case won’t file. That’s the only competitive advantage a self-represented homeowner needs.
