Avista Corp. received state approval to raise rates starting Jan. 1.

The utility’s Washington ratepayers will pay 4.6 percent more for electricity. That’s about $3.10 more per month, raising the average bill to about $81.93.

Avista also will collect 2.4 percent more for natural gas, adding an extra $1.83 to the average monthly bill, bringing the charges to $66.69.

The rate hikes were approved Friday by the three-member Washington Utilities and Transportation Commission. As part of the agreement, Avista will not be able to seek another rate increase until April 2012.

The commission noted in a press release that Avista initially sought higher rate increases before reaching an agreement in September. Along with approving the rate settlement, the commission has asked Avista for “a more detailed breakdown of wages, bonuses and executive compensation to assist in further analysis.”

The commission noted that comments and concerns by Avista ratepayers during public hearings regarding executive compensation prompted the request for additional materials.

Avista has until Feb. 29 to respond to the commission request for information.

Company spokeswoman Debbie Simock said Avista is satisfied with the rate increases, which are expected to bring an additional $23.7 million in revenues.

Avista sells electricity to 234,000 ratepayers in Washington. The company sells natural gas to 147,000 ratepayers.