Express language, no exceptions
Under C.R.S. § 38-31-101, no conveyance or devise of real property to two or more people creates a joint tenancy in Colorado unless the instrument expressly declares it — either that the property is conveyed or devised "in joint tenancy," or to the named people "as joint tenants." Without that declaration, ownership defaults to a tenancy in common, with no survivorship, and a co-owner's share goes through probate.
"Jointly and severally" wasn't enough
A real Colorado Supreme Court case shows how strictly this gets applied. A will left property to two people "jointly and severally" after paying debts and expenses. When one of the two beneficiaries died before the person who wrote the will, and that will-writer had no known heirs, the outcome hinged entirely on whether the devise created a joint tenancy or a tenancy in common — if it was a tenancy in common, the deceased beneficiary's share risked passing to the state instead of to his surviving co-beneficiary. A trial court had read the will as creating a joint tenancy, but the phrase "jointly and severally" doesn't expressly choose joint tenancy the way the statute requires, and Colorado courts have treated that kind of ambiguous language as insufficient on its own to create survivorship.
A 2008 law brought back the old test
Colorado's joint tenancy law itself has gone through a notable shift. For years, courts moved away from the traditional common-law "four unities" — time, title, interest, and possession — toward a looser standard based on the parties' actual intent, and Colorado's Supreme Court had suggested in dicta that the four unities doctrine had been abolished entirely by statute. The 2008 Colorado Joint Tenancy Act (House Bill 08-1248) responded directly to that: it amended § 38-31-101 to state that the four unities doctrine "is continued" as part of Colorado law, reinstating a more structured framework rather than relying purely on intent.
An owner can name themselves as a joint tenant
One modern flexibility survived that 2008 shift: any grantor in a conveyance can also be one of the named grantees. That means a sole owner of Colorado real estate can create a joint tenancy simply by conveying the property back to themselves and one or more other people as joint tenants, without needing to route the transaction through an intermediary "strawman" the way older common-law rules once required.
No extra wording needed once the core phrase appears
Colorado doesn't require a more elaborate phrase on top of the basic joint tenancy declaration. The abbreviation "JTWROS" and phrases like "as joint tenants with right of survivorship" or "in joint tenancy with right of survivorship" carry exactly the same legal meaning as the simpler "in joint tenancy" or "as joint tenants" — once the core declaration is there, survivorship is understood as part of it.
A newer tool, with its own quirks
Joint tenancy isn't the only way to keep Colorado real estate out of probate. See our guide to the Colorado beneficiary deed for a tool that works without a co-owner — and for why it interacts with an existing joint tenancy in a way that can surprise people.