Hmm CO LL/TT law is interesting. I would do as you do repair it.
REPAIRS AND MAINTENANCE
A tenant who withholds rent until repairs are made can be legally evicted for nonpayment of rent. Neither Colorado nor Boulder law provides for a tenant to make the repairs himself/herself and then deduct these costs from the rent.
Except for common areas and facilities in multi-unit properties, the landlord is required to repair and maintain the premises only if:
1. There is a specific agreement between the landlord and the tenant (such as a lease) which specifies that the landlord is responsible for repairing or maintaining the premises; or
2. There is a specific agreement between the landlord and the tenant that the landlord will make specific repairs (such as an attachment to the lease or a letter of promise); or
3. The repair or maintenance is required to make the property conform to the City of Boulder Housing Code, Section 10-2-1, et seq., B.R.C. 1981, unless the tenant is given this responsibility in the lease. The Housing Code only applies within the Boulder city limits.
The Housing Code covers basic safety and living conditions such as fire safety systems, fire resistive doors and walls, plumbing, water supply, electrical services, mechanical and heating equipment, cooking devices, windows, doors and egress, floors, walls, ceilings, stairways, space requirements, pest control, food preparation and storage areas, and safe maintenance of utilities and equipment. If the tenant believes that a violation of the Housing Code has occurred, the tenant should first contact the landlord to request the necessary repairs. A sample letter to request repairs is available on the Community Mediation Website on-line. If the landlord does not respond, the tenant may call Housing Inspection and Rental Licensing (303-441-3152) to request assistance. The housing inspector will contact the landlord if the problem constitutes a violation of the Housing Code. If the violation is minor, the landlord will be given a reasonable period of time to correct the problem. Enforcement action may be taken by the city when violations are not corrected.
What a Tenant May Do When Repairs are Needed
To determine who is liable for repairs, the tenant should check the lease to see if the lease states who is responsible for maintaining and repairing the premises. If the landlord is responsible, the tenant should first contact the landlord. If the landlord refuses to act promptly, the tenant may then:
1. Present a written list of the needed repairs to the landlord requesting that the repairs be made by a certain date;
2. Offer to help cooperate by arranging to be home when the repair person arrives;
The tenant should always:
1. Keep a copy of any notes or letters to the landlord;
2. Follow-up any verbal agreements with the landlord by a letter confirming the agreement;
3. Be reasonable in allowing the landlord time to make the repairs;
4. Follow-up with a written reminder to the landlord if the repairs have not been made.
When Repairs are not made in timely fashion:
If the landlord was obligated to repair (through a lease, Housing Code, or some other agreement), and repairs were not made, a tenant may be able to receive some financial compensation for not having the repairs completed or use of the amenities (such as appliances or a flooded room). The determination of how much less a rental home was worth because the repairs were not made is a negotiation. The tenant may ask the landlord for a decrease in rent. The concept of rent reimbursement is known as diminished value of the premises. Consult an attorney before you attempt this as principles of contract law are involved.
Source CO Landlords-Tenants Handbook