Conn. Gen. Stat. § 12-38: Interest on taxes, fees and assessments due from municipality to the state.

All taxes, fees and assessments due the state from towns, cities or boroughs shall be liable to interest at nine per cent per annum when payment of the same has been delayed more than thirty days after the time prescribed by law for the payment thereof, provided the minimum amount of interest on any such tax, fee or assessment shall be five dollars.