Lower your Boulder County property taxes
The Boulder County Assessor revalues homes in Boulder, Longmont, Lafayette, Louisville and the mountain towns every two years, and 2027 values will reflect the market as of June 30, 2026. The median residential value dipped about 1% in 2025, but high-priced homes with few true comparables are easy to overvalue. 30% of first-year savings, only if you save.
What a too-high value costs you
If your home is assessed at $800,000 but similar homes point to about $740,000, you're taxed on $60,000 too much. At a 0.62% rate that's about $372 a year. Our fee would be $112; you'd keep $260.
What gets missed in Boulder County
- The 2027 reappraisal. Every home gets a new value in May 2027, based on sales up to June 30, 2026. Each reappraisal is a fresh chance to protest.
- Few true comparables. Unique and high-end homes in Boulder have few matching sales, so the model leans on homes that differ.
- Tax areas vary widely. Total levies run from about 87 mills in parts of Boulder to over 160 in parts of Longmont and Lafayette.
- Condition. An original kitchen, an aging roof or a cracked foundation doesn't show up in the assessor's records.
Insider tip: Boulder County accepts appeals by email, mail, drop box, fax, online and in person. Board of Equalization hearings are held by video or phone, so have your evidence ready in digital form.
Reviewed by the founder
Julien reviews every Boulder County case personally and tells you the value we’ll ask for before anything is filed.
Get my free reviewBoulder County calendar
| June 30, 2026 | Appraisal date: 2027 values reflect the market on this day |
| By May 1, 2027 | Boulder County Assessor mails Notices of Valuation (May 1 is a Saturday) |
| May 1 – June 8, 2027 | File your protest with the Boulder County Assessor |
| By August 15, 2027 | Boulder County Assessor sends written Notices of Determination |
| September 15, 2027 | Deadline to appeal to the Boulder County Board of Equalization |
| By November 1, 2027 | Boulder County Board of Equalization decides appeals |
| 30 days after the decision | Appeal to the Board of Assessment Appeals, binding arbitration or district court |
| January 2028 | Tax bills for 2027 mailed |
Sources: Boulder County Assessor — real property appeals · Boulder County — Board of Equalization · Boulder County — tax calculation. Dates are checked each year; confirm with the county for your property.
Exemptions to check
If you're 65 or older and have owned and lived in your home for at least 10 years, the senior exemption takes 50% off the first $200,000 of actual value. The county says that usually saves $500–$700 a year. For 2026, the local-government part of your tax is figured on your value minus 10% of the first $700,000. We check your exemptions free at sign-up.
Boulder County questions
How do I appeal in Boulder County?
Online, by email to the Assessor, by mail, at a drop box or in person, by 11:59 p.m. on June 8.
When will I hear back?
Boulder used the later reappraisal-year schedule in 2025: Notices of Determination by August 15 and Board of Equalization appeals by September 15. The Board decides by November 1.
Can I appeal my tax bill instead?
No. Only the value can be appealed, not the tax. Lowering the value is what lowers the bill.