Colorado is the split-rate biennial state. Every real property parcel is reassessed in odd-numbered years only — the 2025/2026 cycle is active now, with a statutory appraisal date of June 30, 2024. The residential assessment rate is split: 6.4% of actual value for local government levies and 7.15% for school district levies (HB24B-1001, August 2024 Special Session). On a $600,000 home, that blended rate produces a taxable basis roughly 3–4× lower than in most other states — which means the absolute dollar stakes of any given percentage over-assessment are lower but still real. The appeal you should prioritize is often not the one your assessor's notice suggests: classification disputes (non-residential 27% vs. residential 6.4%) dwarf any market-value argument, and time-adjustment factor attacks on the assessor's trending model can move values across entire neighborhoods when the county has overstated 18-month appreciation in a specific sub-market. See the §6 Editor's Note.
| Metric | Value |
|---|---|
| Statutory valuation standard | Actual value = market value as of the appraisal date (C.R.S. §39-1-103(5)) |
| Appraisal (valuation) date | June 30 of the even-numbered year preceding the reassessment cycle — June 30, 2024 for the 2025/2026 cycle |
| Lien date | January 1 at 12:00 noon of the tax year (C.R.S. §39-1-107) |
| Reassessment cycle | Biennial — odd years only (2025, 2027, 2029). Values carry over in even-numbered intervening years unless physical condition or classification changes |
| Sales base period (2025/2026) | January 1, 2023 – June 30, 2024 — sales outside this window are inadmissible for residential valuation |
| Residential assessment ratio | 6.4% of actual value for local government levies; 7.15% for school district levies (HB24B-1001, 2024 Special Session) |
| Non-residential assessment ratio | 27% (2025); declining to 26% (2026) and 25% (2027) for commercial and agricultural |
| Assessor protest deadline | June 8 (real property; postmark or in-person delivery) |
| CBOE appeal deadline (standard) | July 15; CBOE must conclude hearings by August 5 |
| CBOE appeal deadline (alternate) | September 15 in counties using the alternate procedure (Adams, Douglas); hearings conclude by November 1 |
| BAA / Court / Arbitration deadline | Within 30 days of date CBOE decision is mailed |
| Filing fees (Assessor + CBOE) | $0 |
| BAA filing fee | $0 for first 2 pro se petitions; $33.75 for 3rd+ pro se; $101.25 per petition if represented by attorney or agent |
| Burden of proof | Taxpayer bears burden by preponderance of evidence |
| Evidence approach (residential) | Market approach (comparable sales) only — income approach legally prohibited for residential (C.R.S. §39-1-103(5)(a)) |
| "No-raise on appeal" rule | None — BAA hearings are de novo; assessor may present evidence for a higher value (rare in practice) |
| Tax payment during appeal | Full payment required by standard deadlines — first half by end of February; second half by June 15; or full payment by April 30. Refunds issued with interest if appeal succeeds |
| Senior homestead exemption | 50% of first $200,000 actual value exempt (max $100,000 AV reduction); age 65+; 10 consecutive years ownership + primary occupancy; no income limit; application deadline July 15 (Colo. Const. Art. X §3.5; C.R.S. §39-3-203) |
| Disabled veteran exemption | 50% of first $200,000 actual value exempt; 100% permanent/total service-connected disability OR "individual unemployability" status (Amendment G, effective 2025) (C.R.S. §39-3-203) |
Valuation principle. Colorado assessors determine "actual value" — defined in C.R.S. §39-1-103(5) as the market value of the property as of the statutory appraisal date. For residential property, this is the price at which the property would exchange between a willing buyer and a willing seller, both with reasonable knowledge of relevant facts and neither under compulsion. For commercial, industrial, and mixed-use property, the assessor may consider market, cost, and income approaches as appropriate. The income approach is legally prohibited for residential single-family property (C.R.S. §39-1-103(5)(a)).
The math.
Actual Value (AV) = Assessor's market-value estimate as of June 30, 2024
Taxable Value (residential) =
AV × 6.4% [local government portion]
AV × 7.15% [school district portion]
Annual Tax Bill = Taxable Value × Mill Levy Rate ÷ 1,000
(Mill levy varies by jurisdiction; Denver metro typical range: 60–100 mills)
Example: $600,000 AV home in a jurisdiction with 80 total mills (blended):
Local taxable basis: $600,000 × 6.4% = $38,400
School taxable basis: $600,000 × 7.15% = $42,900
Approximate blended annual bill: ~$40,650 × 80 ÷ 1,000 ≈ $3,252
Reassessment mechanics.
(a) General reassessment cycle. Colorado conducts a statewide biennial reassessment: all real property is revalued in odd-numbered years. The 2025 reassessment is the current active cycle, using a statutory appraisal date of June 30, 2024 and a sales base period of January 1, 2023 through June 30, 2024. The 2026 tax year is an intervening year — values from the 2025 reassessment carry over unchanged unless a qualifying change occurs.
(b) Mid-cycle individual reassessment triggers. Even in intervening years, a parcel's value or classification can change if: new construction is added or completed; existing improvements are demolished or substantially destroyed; a split, subdivision, or consolidation changes the parcel configuration; a factual error is corrected by the assessor; or a classification change is ordered. An intervening-year re-notice triggers its own protest window.
(c) Annual mechanisms between reassessments. Between reassessment cycles, the base assessed value from the prior odd-year reassessment remains fixed for most properties. Local mill levy rates are adjusted annually through local government and school district budget processes, meaning your actual tax bill can change even in an intervening year without any change to your assessed value. HB24B-1001 (August 2024 Special Session) capped local government property tax revenue growth at 5.25% per year (6% for school districts), limiting upward pressure on mill levies in intervening years.
Two appealable error types. Colorado allows appeals on two independent grounds: (1) market value dispute — the assessor's estimate of actual value as of June 30, 2024 is too high, supported by comparable sales within the base period; and (2) classification dispute — the property is incorrectly classified as non-residential (27% ratio) when it qualifies as residential (6.4%/7.15%), or vice versa. Classification disputes produce multiplicatively larger tax corrections than market-value disputes and are the highest-leverage appeal type for transitional or mixed-use properties.
Local administrative structure. Colorado has 64 counties, each with a separately elected County Assessor who sets values. There are no townships. Each county has its own County Board of Equalization (CBOE). The state-level Board of Assessment Appeals (BAA) provides uniform third-tier de novo review for all Colorado counties.
Consider appealing if:
Do not expect to win if:
Your move. Pull 3-5 sales of comparable homes (similar size, age, condition, location) that closed between January 1, 2023 and June 30, 2024. If the adjusted sale prices cluster below your notice value by 5% or more, those sales provide the evidentiary basis for a market-value protest. If your property is near a classification boundary — short-term rental, accessory dwelling unit, small commercial with residential component — check the classification first. That question has a larger dollar impact. Before filing anything, verify whether you qualify for the senior or disabled veteran exemption. That is a zero-protest path to a meaningful reduction. See §7.
Cost of appealing in Colorado.
There is no statutory no-raise protection in Colorado. Because BAA hearings are de novo, the assessor may theoretically present evidence supporting a higher value. This is uncommon in residential practice but is a real consideration for commercial properties where the assessor believes current value is understated.
You receive a Notice of Valuation by May 1 of the reassessment year. You have until June 8 (postmark or in-person delivery) to file a written protest. The assessor reviews your submission and issues a Notice of Determination — typically within 2-4 weeks, though no hard statutory deadline applies. Most counties accept protests by mail, online portal, or in person. Submit comparable sales with a brief explanation of adjustments and request a specific value.
ACTION: File by June 8. Attach 3-5 base-period comparables with dollar-per-square-foot analysis. Request a specific reduced value, not just "lower my assessment."
If the Assessor's determination is unsatisfactory, appeal to the County Board of Equalization. In most counties the deadline is July 15; Adams and Douglas counties use the alternate-calendar procedure extending the CBOE deadline to September 15. The CBOE must conclude hearings by August 5 (November 1 for alternate counties). CBOE hearings are informal — typically 15-30 minutes, you present evidence, the county assessor responds, the board deliberates and issues a determination.
ACTION: File with the CBOE immediately if the Assessor offers no relief. Bring the same comparables plus any additional data gathered since the Assessor protest.
Within 30 days of the CBOE decision mailing, choose one mutually exclusive path: (a) Board of Assessment Appeals — state-level de novo hearing, $0 for first two pro se filings, typically scheduled 6-18 months out, written decisions; (b) District Court — more formal and expensive, practically requires an attorney, appropriate for high-value commercial disputes; or (c) Binding Arbitration — faster than court, by joint agreement, shared arbitrator costs.
Choose your Tier 3 path at the 30-day mark — they are mutually exclusive. The BAA is the preferred path for most residential appellants: it's accessible, de novo, and far cheaper than court. A successful BAA petition covers both years of the biennial cycle.
What you need to submit:
Common reasons appeals fail:
Theory selection. You have two independent grounds: market-value dispute and classification dispute. For most homeowners, market value is the primary argument. For transitional properties — short-term rentals, accessory dwelling units, mixed-use, garage or basement conversions — classification deserves analysis first. The residential-to-non-residential assessment ratio gap (6.4% vs. 27%) means a successful classification change is worth more than a 75% market-value reduction on the same property.
~35-45% Residential CBOE protests that receive some reduction — Colorado Division of Local Government data shows assessors grant partial relief on roughly one-third to one-half of residential protests filed with comparable sales evidence
4× gap Assessment ratio differential between non-residential (27%) and residential (6.4%) — making Colorado classification disputes among the highest-leverage corrections in this guide series
6–18 months Typical BAA hearing scheduling lag from filing to hearing — the Board is accessible but backlogged; file promptly, pay taxes on time, and collect refunds with interest when you prevail
Pattern 01
The difference between a successful market-value protest and a failed one is almost always the quality of comparable selection, not the number of comparables. Assessors use a mass-appraisal model that applies systematic adjustments within neighborhood codes. Three carefully selected comparables from the same subdivision with minimal gross adjustment outperform ten loosely related properties from a broader area.
Pattern 02
For the 2025 cycle, assessors adjust base-period sales to reflect conditions as of June 30, 2024 using monthly appreciation factors. In volatile sub-markets — mountain communities, specific Front Range corridors, resort-adjacent neighborhoods — these trending factors can overstate appreciation. A successful challenge to the factor systematically reduces the adjusted value of every comparable the assessor cited.
Pattern 03
County property record cards drive the mass-appraisal calculation. GLA errors are common on remodeled properties where permits weren't pulled. Condition and quality ratings — which apply percentage multipliers to base cost — can lag reality after renovations or deterioration. A single condition-grade correction can shift the cost-approach value by 10-15%.
Pattern 04
Colorado's short-term rental market has created a classification battleground in mountain counties (Eagle, Summit, Pitkin). Assessors have reclassified active STRs as lodging (non-residential, 27%) based on commercial use intensity. A successful reclassification to residential cuts the effective assessment ratio by more than 75%. The outcome turns on owner-use percentage, occupancy patterns, and whether a business license is held.
Colorado assessors apply paired-sales analysis within each neighborhood code to establish per-square-foot base rates, then apply adjustments for age, condition, quality grade, and lot characteristics. Your comparables need to be from the same neighborhood code (or sufficiently close) and require minimal gross adjustment. The BAA looks unfavorably on comparable grids with cumulative adjustments exceeding 25-30% of sale price.
Request the assessor's neighborhood code map and comparable sales grid during your Assessor protest. Knowing which sales the assessor selected — and why — lets you challenge specific adjustments rather than arguing past each other with different sets of comparables.
For the 2025 cycle, the base period runs January 1, 2023 through June 30, 2024. A sale from January 2023 must be adjusted upward to reflect conditions at June 30, 2024 — the appraisal date. Colorado assessors apply a monthly trend factor derived from county-wide or neighborhood-level sales analysis, typically 0.3-0.8% per month appreciation for most Front Range markets during this period.
If a specific sub-market appreciated less than the county-wide trend — a mountain neighborhood with seasonal price volatility, a condo building with specific structural issues, an urban corridor affected by new development — you can challenge the trend factor with internal sales data. Pull paired sales (the same or very similar properties sold twice within the base period) and compute the actual implied monthly appreciation. If the county applied 0.5%/month but your paired sales show 0.3%/month, every 18-month comp adjustment is overstated by roughly 3.6% — on a $600,000 property, a $21,600 systematic inflation before comp selection is even argued.
County assessors derive cost-approach values from property record cards built from building permits, prior sales data, and periodic field inspection. Errors accumulate when: permits weren't pulled for additions or renovations (the assessor doesn't know about added square footage); a basement is finished after the last inspection; a detached garage or outbuilding was added without a permit; or the condition or quality grade was set from a drive-by that didn't reflect interior condition.
Request your property record card from your county's public records portal. Review: total GLA in finished above-grade and below-grade categories; year built and effective age; bedroom and bathroom count; heating and cooling system; condition rating (poor/fair/average/good/very good/excellent); and quality grade. Discrepancies between the record card and actual property conditions form the basis for a factual-error correction, which flows through the mass-appraisal calculation automatically.
Colorado's STR classification battleground emerged as mountain-county assessors began reclassifying vacation rentals from residential (6.4%/7.15%) to lodging or commercial (27%). The legal question under C.R.S. §39-1-102(7.5) and (14.4) is: what is the "primary use" of the property?
Factors that strengthen the residential classification argument: personal use exceeding 14 days or 10% of days rented; management by the owner rather than a commercial property management company; lack of a formal business license; absence of commercial-scale amenities. Properties managed through Airbnb or VRBO by an owner who also uses the property personally have the strongest residential classification case. Mountain counties with active STR reclassification programs — Eagle (Vail), Summit (Breckenridge/Keystone), Pitkin (Aspen), and portions of Jefferson and Larimer counties — are the highest-risk jurisdictions.
| Exemption | Eligibility | Benefit | Statute | Deadline |
|---|---|---|---|---|
| Senior Homestead Exemption | Age 65+ by Jan 1; owned and occupied as primary residence for 10+ consecutive years preceding Jan 1; no income limit | 50% of first $200,000 actual value exempt (max $100,000 AV reduction) | Colo. Const. Art. X §3.5; C.R.S. §39-3-203 | July 15 |
| Disabled Veteran Exemption | 100% permanent and total service-connected disability rating; OR "individual unemployability" status (Amendment G, effective 2025); primary residence | 50% of first $200,000 actual value exempt (max $100,000 AV reduction) | Colo. Const. Art. X §3.5; C.R.S. §39-3-203 | July 15 |
| Surviving Spouse Exemption | Surviving spouse of a qualifying senior or disabled veteran receiving the exemption at time of death; must continue occupying the same residence; no age requirement | Same benefit as deceased spouse's exemption | C.R.S. §39-3-203(1.5) | July 15 |
| Agricultural Land Classification | Land actively used for agricultural production — valued at earning capacity, not market value | Eliminates development-value premium from assessed value; produces very large effective reductions on land with development potential | C.R.S. §39-1-102(1.6); §39-1-103(5)(a) | Annual determination |
| Conservation Easement | Donation of development rights to a qualified land trust or government entity; permanently removes development premium | Reduction in actual value proportional to the value of development rights donated | C.R.S. §38-30.5-101 et seq. | Permanent once recorded |
| Religious / Charitable / Educational | Property owned by a qualifying non-profit and used for exempt purposes | Full exemption from property taxation | C.R.S. §39-3-101 et seq. | Application to county assessor |
Senior exemption: the no-income-limit advantage. Unlike most state senior property tax relief programs, Colorado's homestead exemption has no income ceiling. A retiree on a $1 million Boulder or Denver home qualifies equally with a retiree in a $200,000 rural home, provided the 10-year ownership-and-occupancy requirement is met. This is structurally unusual — California, Illinois, and Texas all impose income limits on comparable programs. Apply by July 15 of the year you first qualify; the exemption renews automatically in subsequent years. Apply at your county assessor's office or through their online portal.
The 10-year continuous-occupancy requirement is strictly enforced. If you moved out and rented the property — even for one year — within the 10-year lookback, the clock typically restarts. Vacation properties that are not your primary residence year-round generally do not qualify. Confirm your eligibility with your county assessor before applying.
Denver is Colorado's only consolidated city-county, giving the Denver County Assessor jurisdiction over the full range of property types within a 155-square-mile urban footprint. The Assessor's office maintains an online Denver Property Search portal with property record cards, assessment history, and comparable sales data that is more detailed than most Colorado county systems.
Denver condominium assessments generate a high volume of protests because the assessor must use condominium comparable sales — not single-family sales — for a market that varies dramatically by building, floor, and unit line. High-rise and mid-rise condo owners benefit from pulling only same-building or same-tier comparables. Cross-building adjustments that attempt to compare a 2023 downtown high-rise sale to a 1980s mid-rise are viewed skeptically at the CBOE and BAA.
Jefferson County spans from urban western Denver suburbs (Lakewood, Wheat Ridge, Arvada) into the foothills (Golden, Evergreen, Conifer) and the mountains (Conifer, Bailey). The geographic range creates sharply distinct sub-markets. Urban single-family homes have dense comparable availability; mountain properties often have sparse comparables and time-adjustment disputes are more viable.
For Jefferson County mountain properties (zip codes 80439, 80433, 80470), the trending-factor challenge (see §6) is particularly viable: mountain-community price appreciation can diverge significantly from the county-wide trend the assessor's mass-appraisal model applies. A Conifer home may have appreciated at a different rate than an Arvada home during 2023-2024, even though both are in Jefferson County.
Arapahoe County contains the bulk of the City of Aurora — Colorado's third-largest city — along with wealthy enclaves including Cherry Hills Village and Greenwood Village. The county's mix is predominantly residential suburban single-family and multi-family, with significant commercial concentration along the I-225 and I-25 corridors.
Upper-tier Arapahoe County properties (above $700K in Cherry Hills, Greenwood Village) should verify whether the assessor's comparable selection reflects the actual upper tier of their market. Appreciation rates diverged between price tiers in the 2023-2024 base period, with entry-level properties in Aurora appreciating more rapidly than high-end enclaves — a county-wide trend factor may overstate appreciation on luxury properties.
Adams County uses the alternate extended CBOE calendar — your CBOE appeal deadline is September 15, not the standard July 15. This extended window gives Adams County property owners more preparation time after receiving the Assessor's Notice of Determination.
Adams County encompasses northern Denver metro communities and the industrial corridor along I-76 and US-85 (Commerce City, Brighton). The commercial and industrial properties along these routes — including refineries, distribution centers, and logistics facilities — generate significant assessed value and are among the more actively contested commercial valuations in the Denver metro.
El Paso County is Colorado's second most populous and home to Colorado Springs, a major military hub (Peterson SFB, Fort Carson, Schriever SFB, NORAD). Military-adjacent neighborhoods saw significant appreciation during 2022-2024 as base expansions drove demand — Fountain, Security-Widefield, and Falcon properties benefited from spillover demand from on-base housing shortfalls.
El Paso County's online property search portal provides the comparable sales data the assessor uses, which is useful for pre-protest comparison. Colorado Springs condominiums — particularly near UCCS or the downtown district — can be difficult to comp because the market is thinner than the Denver metro; assessors sometimes stretch geographically for comparables in a way that overstates adjusted values.
Boulder County has the highest median home values in Colorado outside of mountain resort counties, driven by the City of Boulder's constrained land supply, CU Boulder university demand, and a concentrated tech and research employment base along the US-36 corridor.
Boulder County's highest-value properties (estates, large lots adjacent to open space) have very thin comparable markets — few similar properties sell in any given year. When comparables are scarce, the assessor's mass-appraisal model relies more heavily on cost approach and location adjustment factors, creating opportunities for condition-based and trending-factor challenges that are harder to mount in denser suburban markets.
Larimer County encompasses the Northern Colorado metro (Fort Collins, Loveland) plus mountain and gateway communities (Estes Park, Allenspark, Red Feather Lakes). Fort Collins is home to Colorado State University, which creates rental-housing demand distinct from typical single-family suburban markets.
Estes Park and Larimer County mountain properties are subject to the same STR classification tension visible in Summit and Eagle counties. Properties near Rocky Mountain National Park with high annual occupancy rates and commercial management face assessor scrutiny over residential vs. lodging classification. Owner-use percentage and the nature of management are the key factual distinctions.
Douglas County is among the wealthiest counties in Colorado by median household income, with premium suburban communities (Highlands Ranch, Castle Pines, Parker) producing above-average assessed values per parcel. Like Adams County, Douglas uses the alternate extended CBOE calendar: file CBOE appeals by September 15.
Douglas County's concentrated upper-middle-market residential (homes in the $600K–$1.5M range) means the dollar stakes of individual appeals are higher than most Colorado counties. The suburban tract development provides abundant comparables, making the standard market-value approach highly feasible — if the assessor's value is above comparable support, the evidence is generally available to prove it.
Weld County is Colorado's largest county by geographic area and one of the most economically diverse — it spans major agricultural land and one of the most active oil and gas producing regions in the country (the Denver-Julesburg Basin). Oil and gas minerals and surface rights generate significant assessed value under a separate valuation framework from residential real property.
Agricultural landowners in Weld County should pay close attention to agricultural classification eligibility (C.R.S. §39-1-102(1.6)) — qualifying farming and ranching operations are valued at earning capacity rather than development-potential market value, producing very large effective reductions on land that would otherwise carry a development premium.
Broomfield is Colorado's second consolidated city-county (after Denver), created in 2001 by carving portions from Adams, Boulder, Jefferson, and Weld counties. At approximately 75,000 residents, it is the smallest Colorado county by population. The community is predominantly upper-middle-market suburban residential with significant technology employment (Oracle, Ball Aerospace, and several large data centers).
Broomfield's small size means the CBOE hears a manageable case volume, and hearings tend to be less adversarial than larger counties. The tech-sector employment concentration produces above-average home values, making the dollar impact of comparable-based appeals meaningful even on relatively modest percentage discrepancies from the assessor's value.
Proposition HH and its aftermath (November 2023). Colorado's 2023 biennial reassessment produced statewide residential value increases averaging 30-40% in many Front Range counties, generating widespread concern about tax bill increases. The legislature passed SB23-303 in the regular session, placing Proposition HH on the November 2023 ballot. Prop HH proposed reducing residential assessment rates while redirecting TABOR surplus refunds to local governments as backfill. Voters rejected Proposition HH decisively — 57% against — reflecting distrust of the proposed TABOR diversion mechanism. SB23-303 was voided by the measure's failure.
SB23B-001 (November 2023 Special Session). The legislature convened immediately after Prop HH failed. SB23B-001 provided emergency one-year relief for the 2023 tax year: the residential assessment rate was set at 6.7% (down from the prior 6.95%) and an additional $55,000 of actual value was deducted from residential property before applying the assessment rate. This was a one-year patch, not a permanent change.
HB24B-1001 (August 2024 Special Session). Facing competing citizen initiative campaigns for November 2024 (Initiatives 50 and 108, which would have imposed stricter constitutional limits on property tax revenue growth), the legislature passed HB24B-1001 in a bipartisan August 2024 special session. The law established the current split residential assessment rate — 6.4% for local government levies, 7.15% for school district levies (effective 2025; dropping to 6.25%/7.05% in 2026); set commercial and non-residential rates declining to 26% (2026) and 25% (2027); capped property tax revenue growth for local governments at 5.25% per year (6% for school districts); and cleared the path for both citizen initiatives to be withdrawn from the November 2024 ballot.
What this means for your 2025 appeal. The 2025 reassessment operates under the HB24B-1001 rate structure. The split 6.4%/7.15% residential rate (2025) and 27% non-residential rate are fixed by statute — they are not appealable. An appeal reduces your actual value; the applicable rate is then applied to the reduced value. The revenue growth cap constrains what local governments can collect from the reassessment but does not affect individual assessments or the appeal process.
At the Assessor level, a Notice of Determination typically arrives within 2-4 weeks of your protest, though no hard statutory deadline applies. The CBOE schedules hearings through August (or November for alternate-calendar counties) — you'll typically receive a hearing date 2-6 weeks after filing. The BAA is the significant time commitment: filing deadlines are 30 days after the CBOE decision, but BAA hearings are typically scheduled 6-18 months after filing due to caseload volume. Written BAA decisions issue within a few months of the hearing. District Court can take 2-4 years.
If you win at the Assessor or CBOE level, the assessor recalculates your actual value at the level established in the decision and your county treasurer issues a corrected tax bill or a refund with interest on amounts already paid. If you win at the BAA level, the Board orders the county assessor to adjust the value and the treasurer corrects your account. Importantly, a successful appeal establishes the new assessed value for both years of the biennial cycle — a 2025 win reduces your 2026 taxes as well. Interest on refunds runs from the date of original payment and is set by statute.
If you lose at the CBOE, you have 30 days from the date the CBOE decision is mailed to file with the BAA, District Court, or elect binding arbitration. If you lose at the BAA, you may appeal to the Colorado Court of Appeals on questions of law. A loss at any tier does not preclude protesting again in the next reassessment cycle (2027) when new values are set.
Colorado has no statutory no-raise protection for property. At the CBOE and BAA, the assessor may present evidence supporting a higher value, and the hearing body could increase your assessment. In practice this is uncommon for residential homeowners but is a real consideration for commercial properties where the county believes the current value is understated. The risk-of-raise concern is most relevant at the BAA for commercial and investment property above $1 million in assessed value.
Missing the Assessor protest deadline for real property in a standard reassessment year generally forecloses the CBOE and BAA path for that cycle — Colorado's deadlines are statutory and strictly enforced. However, if your property's classification or physical characteristics changed during an intervening year (triggering a new Notice of Valuation), a fresh protest window opens from that notice. A separate process also exists to correct factual errors in the assessor's records — errors in square footage, bedroom count, condition rating — which is distinct from a valuation protest. Confirm your options with your county assessor's office.
No attorney is required at the Assessor protest or CBOE level. The BAA is accessible to self-represented taxpayers — the filing fee is waived for the first two pro se petitions. BAA hearings are formal administrative proceedings with witness examination and evidentiary rules, and for high-stakes commercial disputes or novel classification questions, professional representation earns its keep. Most residential homeowners succeed at the CBOE without representation.
No. Sales after June 30, 2024 are outside the statutory base period and cannot be used to establish your property's value for the 2025/2026 cycle. The assessor is legally required to value your property as of June 30, 2024, regardless of subsequent market changes. Your most effective strategy is finding sales within the base period (January 1, 2023 – June 30, 2024) that support a lower value as of that date.
The CBOE (County Board of Equalization) is a county-level body that conducts informal hearings and issues determinations within the county. The BAA (Board of Assessment Appeals) is an independent state-level body of nine governor-appointed appraisers who conduct formal de novo hearings — meaning the BAA reviews the evidence fresh and is not bound by the CBOE's finding. The BAA's written decisions are reasoned orders that can be appealed to the Court of Appeals on questions of law. The BAA is where a professionally prepared case with appraisal support produces the most value.
Correct. Colorado's constitutional senior homestead exemption (Colo. Const. Art. X §3.5) does not include an income limit. A 70-year-old with $300,000 in annual investment income qualifies equally with a 70-year-old on Social Security, provided the 10-year continuous ownership and primary-occupancy requirement is met. Most comparable state programs cap eligibility at $50,000–$80,000 household income. If you qualify by age and tenure, apply by July 15.
Colorado has a range of service options: national contingency-fee firms that have expanded into the state, local Colorado property tax attorneys, and certified assessor consultants.
National contingency-fee firms. Several national property tax appeal companies — including services operating under the Ownwell, NCSC, and comparable models — have expanded into Colorado, particularly the Denver metro and resort counties. These firms typically charge 25-40% of first-year tax savings, with no fee if no savings are achieved. Before engaging, confirm the firm has licensed Colorado appraisers or certified assessor consultants on staff, and ask specifically whether they handle BAA-tier representation and what their contingency structure is for that level.
Colorado-specific practitioners. The Denver metro has established property tax law firms and consulting practices that work primarily on commercial appeals and higher-value residential disputes. For properties above $500,000 in assessed value, or for classification disputes, a Colorado-licensed appraiser working with a property tax attorney tends to produce the best BAA outcomes.
DIY viability. Colorado's Assessor and CBOE tiers are designed to be accessible without professional help. The evidence requirement — comparable sales within the base period — is researchable through county public records portals. The Colorado Division of Local Government's Assessors' Reference Library is publicly available and explains the methodology the assessor is required to follow, which is useful context for structuring your protest argument.
Ask about BAA coverage before signing. Some contingency-fee firms handle only the Assessor and CBOE tiers — when those produce no result, they decline to escalate to the BAA because the economics of a formal hearing on a residential contingency fee are marginal. Before engaging any service company, confirm whether they will represent you at the BAA, what the additional cost structure is if they do, and what their historical BAA success rate looks like for properties similar to yours.
Colorado statutes:
State agency publications:
County sources:
Methodology note. Colorado property tax law changed substantially between 2023 and 2025. Assessment ratios and revenue growth caps established by HB24B-1001 may be subject to further legislative adjustment. Statutory deadlines (June 8 protest, July 15 / September 15 CBOE) are verified against current statute as of September 2026 but should be confirmed against your specific Notice of Valuation. The §6 Editor's Note describes an analytical approach, not a guaranteed outcome — all appeals turn on specific facts.
Not legal advice. The Property Tax Desk is an editorial publication providing general information about property tax systems. Nothing on this page constitutes legal advice, tax advice, or a recommendation about whether to appeal any specific property assessment. Consult a licensed Colorado attorney or certified assessor consultant for guidance on your situation.
The Property Tax Desk Editorial Team · Last reviewed September 2026 · Sources verified against current statute and state agency publications · Methodology