Under Connecticut law, the per gallon diesel tax may be adjusted up or down effective July 1 of every year, depending on a couple of factors. This year, the rate will increase to 46.5 cents per gallon.
The state diesel tax rate is comprised of two components. One is a base rate of 29 cents per gallon. The second component is calculated annually and is based upon the average wholesale price per gallon of diesel fuel from the period of April 1 through March 30, plus the applicable gross receipts tax rate on petroleum products. The combination of these factors has resulted in the announcement by the Commissioner of Revenue Services that the per gallon diesel tax rate will increase by 2.6 cents per gallon, to 46.5 cents per gallon, effective July 1.