Conn. Gen. Stat. § 12-115
The board of assessment appeals in any town or city may, within three months from the date prescribed by law for the completion of its duties, as set forth in section 12-111, add to the grand list of a town any taxable property which has been omitted by the assessor or board of assessors or the board of assessment appeals, which shall reflect for each owner of such property, an assessment at seventy per cent of the present true and actual value of such owner's taxable property from the best information that it can obtain, and if the owner failed to file the declaration as prescribed by law, shall add thereto twenty-five per cent of such assessment. Such board of assessment appeals shall mail to such owner at the last-known address of the owner, postage paid, within one week after the completion of such supplemental additions to the grand list, a written or printed notice to appear before such board at a stated time and place and show cause why such property should not be added to such grand list. Any person aggrieved by the action of such board may, within two months from the time of such action, have the same right of appeal to the Superior Court as provided by section 12-117a. The authority designated by section 12-130 shall make and sign a rate bill for such supplemental additions to the grand list and a warrant with respect to such additions which shall be forwarded by the tax collector to such person, and such collector shall have the same powers for the collection of the tax based on such supplemental additions to such list as for the collection of other taxes.
Conn. Gen. Stat. § 12-115
(1949 Rev., S. 1799; 1957, P.A. 673, S. 10; P.A. 76-436, S. 305, 681; P.A. 86-102, S. 1, 2; P.A. 87-245, S. 7, 10; P.A. 95-283, S. 54, 68; P.A. 99-189, S. 15, 20.)
Performance of duty may be compelled by mandamus. 103 C. 614. Board is not agent of town under section; its duties are administrative. 107 C. 700. Assessors cannot defend mandamus on ground board subsequently held property left out of list not taxable. 108 C. 259. Where mandamus brought to compel board to add omitted property, it is defense that board had in exercise of honest discretion held property not taxable. 111 C. 427. Cited. 165 Conn. 546; 220 Conn. 335. Cited. 29 Conn.App. 97.