Land · Colorado tax sale guide

Arapahoe County tax sales, Colorado

Verified

Arapahoe County runs its tax lien sale online through RealAuction, which the Treasurer names as the county's vendor for the auction site, at arapahoe.coloradotaxsale.com. The Treasurer's information page walks through the whole bidder path in plain language: register and let the site build the IRS W-9 from the registration information, deposit ten percent of the amount you want to spend by electronic check, and bid premium, with the system paying one dollar over the second highest bid on a win and capping winnings at the deposited bankroll. Two computers are made available in the Treasurer's building during office hours for bidders without one. The county calls the November 5, 2026 sale the 2025 Tax Lien Sale, because it sells the liens for 2025 taxes payable in 2026.

Selling office: Arapahoe County Treasurer

Next sale: 2025 Tax Lien Sale, held online November 5, 2026; completed as of November 9, 2026. The Treasurer's tax lien sale page states the 2025 Tax Lien Sale was held online on November 5, 2026, and that the sale opens for deposits and bidding about a month in advance of the sale date, with the Tax Lien Sale Site open for registration year round. Delinquent real estate tax payments had to be received by the end of the day before the sale closed, and cleared funds (cash, cashier's check, certified check or money order) were required for payments made after September 30. As of November 9, 2026 the 2026 sale is over.

The November 5, 2026 sale is complete. Watch the Treasurer's tax lien sale pages in October 2027 for the next sale files and publication, and the RealAuction site, which stays open for registration year round; the October timing is the county's stated pattern, not a published 2027 date.

Dates and deadlines

Sources: Arapahoe County Treasurer, Tax Lien Sale. Arapahoe County Treasurer, Tax Lien Sale Information. Arapahoe County Treasurer, Property Tax Information. Confirm with the selling office before relying on any date on this page: sales move, terms change, and parcels are pulled up to sale day.

Research Arapahoe County parcels before you bid

A sale list gives you the parcels, the date, and the opening terms. It does not give you the owner, the value, or the rest of the picture: liens, foreclosure status, and parcel history. PropertyRadar is the data platform for that layer. It carries owner records, assessed and market values, foreclosure and tax data, and property history for parcels across Arapahoe County, searchable by address, owner, or county, including parcels that never reach a sale list.

Open a PropertyRadar accountSee plans and pricing

Pine and Brass is a PropertyRadar partner. If you open an account through these links, we may earn a commission; it does not change the price you pay.

How Colorado tax lien sales work

• Unpaid taxes become a lien, and the lien is what sells. Property taxes in Colorado are a lien on the property, and delinquent interest accrues at 1 percent per month under CRS 39-10-104.5. When taxes stay unpaid, the county treasurer publishes the delinquent list once a week for three weeks (39-11-102) and sells the tax lien at the annual sale under Title 39, Article 11. What the buyer receives is a certificate of purchase: a lien position against the property, not the property, not a deed, and no right to enter or use it.
• The sale runs every fall, and the statute sets the outer date. The sale must begin no later than the second Monday in December (39-11-109), and each treasurer fixes the day. Counties in this set sell from late October into December, most of them in November. Most of the large counties sell online through a vendor the treasurer names; some still sell in person, and the county page says which.
• Bidding is a premium, and the premium is spent money. Under 39-11-115(1) the lien goes to the person who pays the taxes, delinquent interest and fees and bids the largest amount on top of that sum. The excess, the premium, is credited to the county general fund. It earns no interest, and it is not returned if the owner redeems. Competition in Colorado raises the price of the lien without raising its return by a cent.
• The rate is fixed by statute, and redemption is the normal exit. The certificate earns the redemption rate in 39-12-103: nine percentage points above the federal discount rate as of September 1, rounded to the nearest whole percent. For the 2026 sale that rate is 13 percent. The owner, or another interested party, may redeem at any time before a treasurer's deed is issued, and the holder may pay later delinquent taxes and endorse them onto the certificate at the same rate. Most certificates end in redemption.
• The deed runs through a public auction now. Colorado used to hand the treasurer's deed to the certificate holder on application after three years. That ended July 1, 2024 under HB 24-1056, and SB 26-144 reenacted the replacement process as Article 11.5 effective June 1, 2026. After August 1 of the third calendar year following the sale, the lawful holder applies, and the treasurer auctions a certificate of option for treasurer's deed: the opening bid covers what is owed to the holder plus treasurer fees and costs, any overbid belongs to the former owner, and if no qualifying bid is made and paid, the lawful holder is deemed the option purchaser and the deed issues to that purchaser. Liens nobody buys are struck off to the county and can later be bought by assignment.

How bidding works in Arapahoe County

Registration is handled by RealAuction at arapahoe.coloradotaxsale.com, and the sale site is open for registration year round. Registration is required to participate and to maintain an existing tax lien buyer number, and no deposit is required to register. No dated registration deadline for the 2026 sale was published on the Treasurer's pages read.

• The premium is the price, and it buys nothing. Every dollar of premium goes to the county general fund the moment the lien sells. A small lien won with a large premium can pay back less than the taxes were worth even at a 13 percent headline rate, because the rate applies only to the certificate amount. Model premium as a fee you pay for the right to earn 13 percent on somebody else's tax bill, because that is what it is.
• The certificate is not the property. No possession, no rents, no right to enter, and no deed on application. Since 2024 the deed runs through a public auction where the owner's equity is bid for openly; buyers who need the property itself on a schedule should be reading the deed state pages, not this one.

Terms: what a bid actually costs

Unsold liens: county held certificates

Liens that draw no bid are struck off to the county, and county held certificates are later available by assignment from the Treasurer on county terms under the Colorado frame. The Treasurer's pages read for this page did not publish a list of Arapahoe county held liens or the county's assignment price and terms for them as of November 9, 2026. Separately, a tax lien holder may assign a held lien to another person, but the assignee must be a registered tax lien buyer before the assignment can be processed.

Before you bid

• Model the premium before the rate. Run the redemption case with your real premium included: certificate amount, plus premium, against 13 percent on the certificate amount alone over the likely redemption window. Liens that only work at a zero premium do not work.
• Check whether the sale is already over. Colorado's season is short and most of it lands in a few November weeks. Several sales in this set had already closed before these pages were checked. The treasurer's sale page is the live word on dates, registration, and deposits.
• Subsequent taxes are part of the position. A holder can pay later delinquent taxes on the parcel and endorse them onto the certificate at the same rate. Budget for carrying the position across the three year deed window, not just for buying it.
• Set the maximum before the sale opens. The free Max-Bid Calculator below works backwards from your exit value to the highest certificate amount you can carry, with the premium and costs shown.

Every Colorado county in this set

One page per county, each verified against its own treasurer source. Colorado has 64 counties; this set is the top 10 by population and sale volume.

• Denver tax sales
• Arapahoe County (this page)
• Jefferson County tax sales
• Adams County tax sales
• El Paso County tax sales
• Douglas County tax sales
• Larimer County tax sales
• Boulder County tax sales
• Weld County tax sales
• Mesa County tax sales

Keep going

Once a deadline puts you in a sale, the Land Investor Due Diligence Toolkit is the checklist and bid worksheet to run on each parcel before you bid. The same desk runs Florida tax deed sales, Texas tax sales, Pennsylvania tax sales, Georgia tax sales, North Carolina tax foreclosure sales, Ohio tax foreclosure sales, Illinois tax lien sales, Michigan tax foreclosure sales, Arizona tax lien sales, California tax defaulted property sales, Colorado tax lien sales and South Carolina tax sales, and the proven New York season, with the live membership, sits in the NY tax sale hub.