Jefferson County, Colorado Property Tax Appeal Guide

Jefferson County, Colorado property owners can challenge their assessor's valuation first with the Jefferson County Assessor's Office, then with the County Board of Equalization (CBOE), and beyond that with the state Board of Assessment Appeals, district court, or binding arbitration. Colorado reassesses real property only in odd-numbered years, and Jefferson County's own valuation materials confirm the county's 2025 revaluation, based on a June 30, 2024 appraisal date, remains in effect for both tax year 2025 (payable in 2026) and tax year 2026 (payable in 2027). That makes 2026 an intervening year: a 2026 Notice of Valuation postcard was mailed only to owners whose value changed because of new construction or other modifications, so most Jefferson County homeowners have no new valuation to protest this year. If you did receive a 2026 change notice and already protested to the Assessor by the June 8 deadline, your live next step is the County Board of Equalization, with petitions due by September 15, 2026. Everyone else's next full appeal opportunity arrives with the 2027 reassessment cycle, when Notices of Valuation go out countywide on May 1.

How assessments work in Jefferson County

The Jefferson County Assessor's Office, led by Assessor Scot Kersgaard, revalues all real property every two years, in odd-numbered tax years, using an appraisal date of June 30 of the preceding even year (June 30, 2024 for the current cycle), drawn from a sales study period of July 1, 2022 through June 30, 2024. The county's April 2025 announcement reported median single-family residential values up 2% since the 2022 revaluation, with a median Jefferson County home value of $632,958; city-level changes varied widely, from Golden at plus 6.9% to Lakewood at plus 0.9% and Mountain View at minus 7.4%, so a countywide average tells you little about your own parcel. Tax is calculated as actual value times the assessment rate times the local mill levy. For 2026, the Assessor's Assessment Rates schedule sets the residential rate at 6.8% for local-government levies and 7.05% for school-district levies, with state law also cutting the value used for local-government calculations by 10% of the first $700,000 of actual value. Mill levies are set separately by each overlapping authority, county, school district, fire district, city, and special districts, so there is no single countywide rate; look up your parcel's own rate through the Assessor's Property Records Search tool.

Whether you should appeal

Appeal if the Assessor's estimate of your actual value, as of the June 30, 2024 appraisal date, exceeds what comparable properties actually sold for during the study period. In a reassessment year like 2025, every owner gets a Notice of Valuation and a real chance to contest it. In an intervening year like 2026, only owners who received a change-driven postcard NOV have anything to appeal; if your value did not change, there is no new determination to protest, and your existing value simply carries through to your 2026 bill. Before filing, pull your property's record from the Assessor's online Property Records Search and use its Sales tab to compare recent transactions matching your home's characteristics; a gap between your assessed value and those comparables is the core evidence any appeal needs.

Step-by-step how to file

When you have a live Notice of Valuation to contest, the Assessor mails it May 1, and appeals run May 1 through June 8, with mailed appeals postmarked no later than June 8. File online through the Online Residential Appeals tool linked from the Assessor's website, or mail back the appeal form attached to your NOV postcard; include comparable sales or record corrections supporting your requested value. The Assessor mails a Notice of Determination on or before August 15. If you still disagree, file a petition with the County Board of Equalization on or before September 15; CBOE hearing officers, appointed by the County Commissioners, review each case, the Board completes hearings by November 1, and written decisions go out within five business days of approval.

What happens after you file

If the CBOE denies your petition in whole or in part, Colorado law gives you three options, each with a 30-day deadline from the date the denial was mailed: appeal to the state Board of Assessment Appeals (a nonrefundable filing fee applies), request a trial de novo in district court, or submit to binding arbitration, whose decision is final and not subject to further review. Business personal property follows a separate, shorter cycle: notices go out by June 15, with appeals due between June 15 and June 30.

If you missed the window

Because 2026 is an intervening year, most Jefferson County homeowners never had a May 1 to June 8 window to miss this year; your 2025 value simply carries forward. If you spot a factual error in your property record outside the normal protest period, the Assessor accepts abatement petitions that can correct valuations for up to two prior tax years. Otherwise, mark your calendar for the 2027 reassessment, when Notices of Valuation again go out countywide on May 1.

Local tips

Start with the Assessor's Property Records Search at propertysearch.jeffco.us before filing anything; its Sales tab surfaces comparable transactions matched to your home. The Assessor's Office also offers online appointment booking if you would rather discuss your value directly. Don't overlook the state-funded senior exemption: homeowners 65 or older who have owned and occupied their home for the ten years preceding the assessment date can have 50% of the first $200,000 of actual value exempted, with applications due by July 15. A same-size exemption is available to veterans rated 100% permanent and total disability by the VA, applying by July 1. Neither exemption is automatic, and once approved you do not need to reapply.