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Tax Sale Atlas

Boulder County, CO tax sales

Tax Sale Atlas maps the Boulder County, CO tax sale, one of 3,131 counties in 51 states. Colorado sells tax lien certificates paying up to 13%. Sale office, calendar and list locations read from the county’s own official pages on Oct 12, 2026.

How tax lien and tax deed sales work in Boulder County, seat of Boulder: sale calendar, auction platform, over-the-counter lists, and the offices that run each sale.

New to tax sales? Read how Colorado tax sales work or look terms up in the glossary.

Next certificate sale
Real-property tax lien auction scheduled for November 13, 2026.Friday · 2026
Format
In person
Registration
What sells is a certificate of option for treasurer's deed, not the parcel outright.
County office
303-441-3520
Every displayed fact carries a source badge. Verified Oct 12, 2026 against official county and state pages.How we verify
On this page
Look up a sale detail

County Treasurer. on application

Record quality: high. Last verified: 2026-10-12.

C.R.S. 39-11.5-102 - Application for public auction (source accessed 2026-07-29)

Recorded reference information. Verify current sale conditions with the county. Read the full sale details.

Link to this detail

How Boulder County sells delinquent taxes

Tax certificate sale (lien)

In person
Run by
Boulder County Treasurer's Office
Frequency
annual
Next certificate sale
Real-property tax lien auction scheduled for November 13, 2026.
Registration
Register in person on the day of the sale.
Next expected
by the second Monday in December, 2026 (window; exact date posts closer to the sale)
Sale list
Tax lien sale advertising list, posted on the Treasurer's tax lien sale page
When it runs
November. The Treasurer's tax lien sale page states "Our tax lien sale will be held Nov. 13, 2026" and its prior-year table lists sale dates of 11/5/2021, 11/16/2022, 11/17/2023, 11/8/2024 and 11/14/2025. On sale day the FAQ states "The sale will begin as soon after 8:30 a.m. as all bidders are registered" and "The auction will last until all properties are sold or until 5 p.m.", with staff deciding whether to continue or adjourn to the next business day.
Registration and deposit

Register in person on the day of the sale. The FAQ states "Registration opens at 7:30 a.m. on the day of the sale" and that "The exact spelling of the name you register with will become the name used on the tax lien certificate." Bidders provide a name, an address for checks and correspondence, a Social Security or Tax ID number, and a completed, signed IRS W-9 form. Registered bidders receive an 8 hour parking pass and park free in four downtown Boulder city lots (11th and Walnut, 14th and Walnut, 11th and Spruce, 15th and Pearl).

Sale format and venue
Boulder County runs its annual tax lien sale as a live, in-person auction, not an online auction. The FAQ gives the sale location as the Boulder County Courthouse, 1325 Pearl Street, Third Floor, Boulder, CO 80302, confirms an auctioneer conducts the sale, and states observers are allowed but seating is limited. No online bidding platform is named on any county page, so verify the format with the Treasurer's Office before planning to bid remotely. Bidding is premium bid: "The auction is open bidding" with no rotation through bidders, and "The bid amount is the premium amount", meaning the amount over and above the taxes, interest and fees on the day-of-sale list. Premium earns no interest and is not refunded; it goes to the County General Fund. The county warns this is a buyer-beware process and gives the example that a 6% premium against a 10% redemption rate loses money if the lien redeems before eight months pass. Recent premiums averaged 5.6% to 7.6% over the last five sales. The interest rate is set by the State of Colorado in September at 9 percentage points above the Kansas City Federal Reserve discount rate, rounded up to the nearest whole percent; the county lists 14% per annum for liens sold in 2025 and 13% per year for liens sold in 2026. Interest accrues monthly on the first day of the month and is paid only on redemption. The auction list is published in the county newspaper of record 4 weeks before the sale for 3 consecutive weeks (Longmont Daily Times-Call, plus the Boulder Daily Camera, Nederland Mountain Ear, Lafayette News, Louisville Times, Lyons Recorder and Colorado Daily in the final week). A current property list is posted on the Treasurer's tax lien sale page near the time of the sale and updated weekly, and printed copies are available at 1325 Pearl Street; the posted spreadsheet is taken down after each sale, so check the sale page in the fall. Boulder County does not offer tax lien certificates over the counter. Subsequent-year taxes may be endorsed onto an existing certificate for a $5 fee, at the original lien's rate, with notices mailed each August. Certificates are held by the Treasurer for safekeeping and copies are mailed within a week of the sale; certificates may be transferred if notarized, recorded with the Boulder County Clerk and Recorder, and accompanied by a new W-9. After three years of unpaid taxes from the original sale, a lienholder may apply for an auction of a Certificate of Option for Treasurer's Deed; the county says less than one half of one percent of its tax liens reach deed. Separately, the county states that delinquent mobile home taxes will be struck off to the county instead of being sold at auction. Third-party aggregator sites list Boulder County sale data; treat only the Treasurer's own pages as authoritative. In person at the Boulder County Courthouse (live auction with an auctioneer)
Source: Boulder County Treasurer's Office - Tax Lien Sale· Verified Oct 12, 2026

Tax deed sale

Run by
County Treasurer
Frequency
on application
Typical timing
There is no fixed calendar.
Registration
What sells is a certificate of option for treasurer's deed, not the parcel outright.
When it runs
There is no fixed calendar. A public auction is scheduled only when a certificate holder applies for one, at least three years after the tax lien sale, and the treasurer must hold it between 110 and 125 calendar days after the known interested party notice is first published or mailed.
Registration and deposit

What sells is a certificate of option for treasurer's deed, not the parcel outright. The treasurer may only accept bids above the combined amount owed to the lawful holder plus the treasurer's fees and costs. County officials, county employees acting in their individual capacity, and their immediate family members may not bid. Payment is by cash, cashier's check, bank check, or electronic funds transfer subject to the treasurer's bidding rules. Any overbid goes to junior lienors who filed a notice of intent to redeem and then to the property owner. Confirm the notice, the bidding rules, and the auction venue with the county treasurer.

Sale format and venue
This Article 11.5 process replaced direct deed issuance on July 1, 2024. Colorado does not hold a routine calendar tax deed sale, so treat this as an occasional, application-driven auction rather than a recurring event.
Source: C.R.S. 39-11.5-102 - Application for public auctionC.R.S. 39-11.5-102· Verified Jul 29, 2026

Boulder County tax sale list and auction calendar

For Boulder County tax sale 2026 searches, use the county-run sources below rather than a copied parcel list, and confirm the parcel, registration cutoff, deposit, and payment deadline against the county before you bid. If the parcels on this list are vacant land rather than houses, what buying land at a tax sale hands you is the place to start.

  1. Confirm the advertised parcel list

    Use Tax lien sale advertising list, posted on the Treasurer's tax lien sale page as a starting reference. Check which sale or list it covers; a Lands Available or office information page is separate from an auction parcel list. Ask the sale office for the advertised parcels for the auction you plan to attend.

  2. Register to bid

    What sells is a certificate of option for treasurer's deed, not the parcel outright. Full requirements are in the sale card above.

  3. Sale day

    Real-property tax lien auction scheduled for November 13, 2026. The sale is live and in person; there is no online bidding platform. Confirm the venue and hour with the County Treasurer before you go.

  4. Confirm with the office

    If the list, platform, and notice disagree, use the County Treasurer as the source to confirm which parcels are actually offered.

Before you bid in Boulder County

  1. Confirm the parcel list before pricing

    Open Tax lien sale advertising list, posted on the Treasurer's tax lien sale page. Confirm whether this reference contains the auction parcels or covers a different list. Get the advertised parcel list from the county before you price a bid, and recheck it before the sale.

  2. Confirm registration and deposit

    What sells is a certificate of option for treasurer's deed, not the parcel outright. The treasurer may only accept bids above the combined amount owed to the lawful holder plus the treasurer's fees and costs. County officials, county employees acting in their individual capacity, and their immediate family members may not bid. Payment is by cash, cashier's check, bank check, or electronic funds transfer subject to the treasurer's bidding rules. Any overbid goes to junior lienors who filed a notice of intent to redeem and then to the property owner. Confirm the notice, the bidding rules, and the auction venue with the county treasurer.

  3. Check the state rules that change the bid

    Read the Colorado due-diligence checklist before bidding. Redemption, liens that survive a tax deed, title cleanup, and payment deadlines can change what a parcel is worth. Which liens survive is state law, so read what survives a tax deed in Colorado before you price the title work.

  4. Set a walk-away number

    Work out what the parcel is actually worth with the rural land value estimator, then turn it into a ceiling with the tax deed max-bid calculator.

Over-the-counter (leftover) purchases

Liens that draw no bid are struck off to the county and the treasurer issues the county a certificate of purchase. The county may then assign, sell, or transfer those certificates in the manner, at the times, and on the terms set by resolution of the board of county commissioners, which is how county-held liens are sold between annual auctions. A certificate on property owing more than ten thousand dollars in taxes needs the property tax administrator's approval after published notice. Whether a county maintains a published county-held list, and on what terms, varies. Contact the county treasurer.

New to this path? Read how over-the-counter certificates work. Every state has its own name for what goes unsold, so check what Colorado calls its leftover tax-sale inventory.

Use the arrow keys to switch between these sections.

County offices

Tax Collector (runs the certificate sale)

Boulder County Treasurer's Office

303-441-3520

P.O. Box 471, Boulder, CO 80306 (public counter: 1325 Pearl St., 1st Floor, Boulder, CO 80302)

Official website

County notes

  • Boulder County holds a live, in-person tax lien auction at the Boulder County Courthouse, 1325 Pearl Street, Third Floor. No online bidding platform is named on the county's pages.
  • Registration opens at 7:30 a.m. on sale day and requires a Social Security or Tax ID number and a signed IRS W-9; bidding starts as soon after 8:30 a.m. as everyone is registered.
  • Bidding is premium bid over the taxes, interest and fees. Premium earns no interest and is never refunded, so a high premium can wipe out the interest yield if the lien redeems early.
  • The rate is 13% per year for liens sold in 2026, down from 14% in 2025. Colorado sets the rate each September at 9 points above the Kansas City Federal Reserve discount rate, rounded up.
  • The county does not sell tax lien certificates over the counter.
  • Delinquent mobile home taxes are struck off to the county instead of being auctioned.
  • The advertising list is posted on the Treasurer's tax lien sale page in the fall and removed after the sale, so the direct spreadsheet link changes each year.

Colorado rules

Max interest rate
13% per year, set by statute (bidding is on price)
Minimum return
No statutory minimum return; what you earn is set by the price at the sale
Redemption
Redemption may be made at any time before a treasurer's deed is executed, so the practical window runs past the three-year mark and into the Article 11.5 process. Once a deed application is pending, the owner must file an intent to redeem with the treasurer no later than seven calendar days before the scheduled public auction, then pay the amount on the redemption statement while it is in effect, and must redeem the entire property. The auction itself is set 30 to 60 calendar days after the treasurer mails the notice of public auction. A separate rule lets an owner who was under a legal disability when a tax deed was executed under Article 11 redeem within nine years of the deed being recorded, at 15 percent per year plus the present value of any improvements.
Deed deposit
The treasurer may require the applying lawful holder to deposit up to one thousand dollars plus statutory fees when the application is accepted, applied against the treasurer's fees and costs, and all Article 11.5 fees and costs are chargeable as additional amounts owing under the certificate of purchase. A third-party winner may be charged up to three hundred dollars for processing. The statute sets no bidder deposit percentage, so payment terms come from the treasurer's written auction policies.
Surplus proceeds
Junior lienors whose liens were recorded before the application for treasurer's deed may file a claim for overbid money within eight business days after the auction. Between the ninth and fifteenth business day the overbid is paid to them in order of recording priority, each up to the unpaid lien plus fees and costs, and whatever remains goes to the property owner. The treasurer mails the owner a notice within thirty days after the claim period ends. Unclaimed overbid stays in escrow for two years without interest to the claimant. Amounts under twenty-five dollars left unclaimed for six months go to the county general fund, and larger amounts left unclaimed for two years go to the state treasurer as unclaimed property. An agreement to pay someone to recover an unclaimed overbid is enforceable only if the fee is capped at ten percent and the agreement is made at least two years after the transfer.
Governing statute
C.R.S. Title 39, Article 11

A tax deed does not convey marketable title. Most buyers file a quiet title action before they can resell or insure the property. See the due diligence guide.

See the full Colorado rules and every county →

Frequently asked questions

Does Boulder County, Colorado sell tax liens or tax deeds?

Boulder County follows Colorado's tax lien state system.

When is the Boulder County tax certificate sale?

November. The Treasurer's tax lien sale page states "Our tax lien sale will be held Nov. 13, 2026" and its prior-year table lists sale dates of 11/5/2021, 11/16/2022, 11/17/2023, 11/8/2024 and 11/14/2025. On sale day the FAQ states "The sale will begin as soon after 8:30 a.m. as all bidders are registered" and "The auction will last until all properties are sold or until 5 p.m.", with staff deciding whether to continue or adjourn to the next business day. The sale is held in person. Always confirm the exact date with the County Treasurer before the sale.

How often does Boulder County hold tax deed sales?

Boulder County tax deed sale schedule: on application. There is no fixed calendar. Each sale is scheduled and advertised in advance, so check the county's tax deed calendar for the next posted date.

I own a property in this sale. Can I stop it?

Often yes, by paying the overdue taxes, interest, and costs before the deadline. Colorado's redemption rule: About 3 years: the certificate holder cannot apply for the treasurer's deed until after August 1 of the third calendar year following the tax lien sale. Call the County Treasurer as early as possible for your exact payoff and options; deadlines are strict. Free help: lawhelp.org lists legal aid programs, and consumerfinance.gov lists HUD-approved housing counselors.

Where can I find the Boulder County tax sale list?

The recorded official list reference is at bouldercounty.gov. Check whether it covers auction parcels, office information or Lands Available, then obtain the advertised parcel list for the sale you plan to bid on. Confirm every parcel against the county's legal advertisement.

Verified Oct 12, 2026 against official county and state sources.

Tax Sale Atlas publishes educational information about public tax sale processes. This is not legal, financial, or investment advice. Rules, dates, and fees change; confirm with the office that runs the sale before you bid.

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Compare sale calendars, platforms, and rules across the state, or read the guides before you bid.

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Call Boulder County Treasurer's Office