Colorado Revised Statutes Title 1. Elections § 1-2-509. Reviewing voter registration applications--notification

(b)(I) If within twenty business days after receipt of the application the notification is returned to the county clerk and recorder as undeliverable, the applicant shall not be registered.

(II) If the notification is not returned within twenty business days as undeliverable, then the applicant shall be deemed registered as of the date of the application; except that, if the applicant was notified that the application was not complete, then the applicant is deemed registered as of the date of the application if the additional information is provided at any time prior to the actual voting. If such applicant does not provide the additional information necessary to make his or her application complete and accurate within twenty-four months after notification is sent pursuant to subsection (2) of this section, the applicant must reapply in order to be registered.

(III) If the notification is returned to the county clerk and recorder as undeliverable after twenty days after receipt of the application, the county clerk and recorder shall mark the applicant's registration record “Inactive” and send a confirmation card.