Arapahoe County, CO tax sales
How tax lien certificate and tax deed sales work in Arapahoe County, seat of Littleton: sale calendar, auction platform, over-the-counter lists, and the offices that run each sale.
Verified Jul 30, 2026 against official county and state sources.
New here? Read how Colorado tax sales work, the difference between a lien and a deed, and redemption periods.
How Arapahoe County sells delinquent taxes
Tax certificate sale (lien)
- Run by
- Arapahoe County Treasurer's Office
- Frequency
- annual
- Typical timing
- One annual online tax lien sale each fall, with bidding opening in early October and closing in early November. The Treasurer's tax lien sale page currently states: "The 2025 Tax Lien Sale will be held online on November 5th, 2026." The prior cycle ran on the same calendar: the published notice said "Pre-Bidding will commence at 8:00 AM MST on October 3, 2025. The auction will close in batches beginning at 8:00 AM MST on November 6, 2025." The county also says "The next online sale of Arapahoe County delinquent tax liens will open for deposits and bidding about a month in advance of the sale" and "The annual tax sale publication will be available in October."
- Next expected
- by the second Monday in December, 2026 (window; exact date posts closer to the sale)
Registration and deposit
Register on the auction site at https://arapahoe.coloradotaxsale.com, which the county says "is open for registration year-round." You submit name, address and similar details, and the site builds an IRS W-9 that is passed to the county. Registration itself costs nothing and requires no deposit, but returning buyers must re-register each year to keep their tax lien buyer number, and every number used by family members or business associates must be registered separately. Before bidding, fund a deposit equal to 10 percent of what you intend to spend, paid by ACH electronic check through the site's deposit wizard. Bidding is by premium: the auction awards each lien to the highest premium bidder at one dollar above the second highest bid, and liens close in batches at times posted on the auction site. Winning bidders pay the remaining balance by ACH or certified check no later than 4:00 p.m. MST on the payment deadline, or they forfeit the bid and the next highest bidder takes the lien. Unused deposits are returned about two weeks after the auction ends. Realauction posts training videos behind the Training link on the sale site, and the county links a practice sale site for new bidders.
The sale is conducted entirely online through Realauction; there is no live courthouse auction. Bidders without a computer can use two machines at the Treasurer's office at 5334 South Prince Street in Littleton, by appointment during office hours Monday through Friday 8:00 a.m. to 4:00 p.m., by calling 303-795-4550. Redemption interest is set by September 1 each year at nine points above the federal discount rate; the county published a rate of 14 percent for the 2025 sale, citing a 4.5 percent federal discount rate and Section 39-12-103, C.R.S. A real property lien must be three years old before the certificate holder can apply for a Treasurer's Deed; for mobile homes the lien must be held one year before applying for a Certificate of Ownership. Parcels carrying unpaid amortized special assessment installments have all future installments brought forward into the total lien amount. Delinquent tax payments must reach the Treasurer's office by end of day the day before the sale closes, and cleared funds are required for payments made after September 30. The Tax Lien Sale Files page also posts a county-held certificates report, the over-the-counter list of unsold certificates the county holds. Timing caution: the county's own page labels the sale "2025" while giving a November 5, 2026 date, and the 2025 published notice shows that sale closing in November 2025, so confirm the current year's exact open and close dates with the Treasurer's office or the auction site before planning deposits.
Register on RealAuctionTax deed sale
- Run by
- County Treasurer
- Frequency
- on application
- Typical timing
- 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.
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.
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.
County offices
Tax Collector (runs the certificate sale)
Notes for Arapahoe County
- Michael R. Westerberg is the Arapahoe County Treasurer, listed on the department contact page and signing the published sale notice.
- The county's Delinquent Tax Publications page carries the newspaper notices for real property, personal property and mobile homes; the 2025 real estate notice ran Thursday October 9, 16 and 23, 2025.
- The Viewable File page is populated only in the weeks before the sale; the county states the viewable file "is available only up to three weeks before the tax lien sale begins," and it currently shows an older cycle's dated files.
- The Supplemental Sale File page reports no supplemental file available at this time.
- The Treasurer's office publishes a standing disclaimer that it cannot warrant anything about any lien sold, that liens may not be first or only liens, and that bidders must do their own due diligence.
Colorado statewide rules
- Redemption
- Redemption may be made at any time before a treasurer's deed is executed, so the practical window runs well past the three-year mark and through the Article 11.5 auction process. The treasurer must hold that public auction between 110 and 125 calendar days after the known interested party notice is first published or mailed, which gives owners and junior lienors a further defined period to pay. A separate rule lets an owner who was under a legal disability when the deed was executed 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 post a deposit covering the recording fee plus the actual and reasonable cost of administering the auction, and all Article 11.5 fees and costs are chargeable as additional amounts owing under the tax lien. For bidders, the treasurer accepts cash, cashier's check, bank check, or electronic funds transfer subject to the treasurer's bidding rules. The statute sets no fixed bidder deposit percentage, so the deposit terms come from county bidding rules.
- Surplus proceeds
- Any overbid goes first to junior lienors in order of recording priority, measured as of the recording date of the application for public auction, who filed a notice of intent to redeem and whose liens are unredeemed, up to each lien's unpaid amount plus fees and costs. Whatever remains is paid to the property owner. The treasurer must post a public notice about these funds and mail the owner a notice within thirty calendar days of the auction. Unclaimed remaining overbids sit in escrow for six months without interest, then transfer to the state administrator under the Revised Uniform Unclaimed Property Act. An agreement to pay someone to recover an owner's overbid is unenforceable, and inducing one is a class 2 misdemeanor.
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.
Frequently asked questions
Does Arapahoe County, Colorado sell tax liens or tax deeds?
- Arapahoe County follows Colorado's tax lien state system.
When is the Arapahoe County tax certificate sale?
- One annual online tax lien sale each fall, with bidding opening in early October and closing in early November. The Treasurer's tax lien sale page currently states: "The 2025 Tax Lien Sale will be held online on November 5th, 2026." The prior cycle ran on the same calendar: the published notice said "Pre-Bidding will commence at 8:00 AM MST on October 3, 2025. The auction will close in batches beginning at 8:00 AM MST on November 6, 2025." The county also says "The next online sale of Arapahoe County delinquent tax liens will open for deposits and bidding about a month in advance of the sale" and "The annual tax sale publication will be available in October.". Registration and bidding happen on the county's online platform. Always confirm the exact date with the Tax Collector before the sale.
How often does Arapahoe County hold tax deed sales?
- on application. Each sale is scheduled and advertised in advance, so check the county's tax deed calendar for the next posted date.
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 county office before you bid.
Explore all 64 Colorado counties
Compare sale calendars, platforms, and rules across the state, or read the guides before you bid.