Here what I was able to find
Colorado Statutes of Limitation
Domestic and foreign judgments: 6 years and renewable each six years. Note: If for child support, maintenance or arrears the judgment (lien) stays in effect for the life the judgment without the necessity of renewal every six years.
All contract actions, including personal contracts and actions under the UCC: 3 years (C.R.S. 13-80-101), except as otherwise provided in 13-80-103.5; All claims under the Uniform Consumer Credit Code, except sections 5-5-201(5); All actions to recover, detain or convert goods or chattels, except as otherwise provided in section 13 -80-103.5.
Liquidated debt and unliquidated determinable amount of money due; Enforcement of instrument securing the payment of or evidencing any debt; Action to recover the possession of secured personal property; Arrears of rent: 6 years, (C.R.S. 13-80-103.5)
Looks to me like the SOL is 6 years -- (Enforcement of instrument securing the payment of or evidencing any debt)