Conn. Gen. Stat. § 12-127: Abatement or refund on proof of exempt status.

Any person who has been unable to submit evidence of blindness as required by section 12-92 or of other claim for exemption as required by section 12-93 may, when he obtains such evidence satisfactory to the assessors, make application to the collector of taxes, within one year after he obtains such evidence, for abatement in case the tax has not been paid, or for refund in case the whole tax has been paid, of such part or the whole of such tax as represents the exemption. Such abatement or refund may be granted retroactively to include the assessment day next succeeding the date as of which such person was entitled to the exemption, but in no case shall any abatement or refund be made for a period greater than one year.