Avista Corp., of Spokane, would be able to raise electric and natural gas rates in Washington on Jan. 1, but not as much as it originally had proposed, if a settlement agreement is approved by the Washington Utilities and Transportation Commission.

The settlement would authorize Avista to increase its annual electric base revenues by 1.4 percent, or $7 million, and annual natural gas base revenues by 5.6 percent, or $8.5 million, according to new releases that it and UTC staff members issued today.

Avista earlier had asked the state to approve increases of 3.8 percent, or $18.2 million, in annual electric revenues, and 7.8 percent, or $12.1 million, in natural gas revenues.

Under the agreement, a residential electric customer’s bill would increase about 2.5 percent. An average residential customer using 965 kilowatt-hours could see an increase of $2.10, for a monthly bill of $82.19. The revised monthly bill includes a proposed increase in the basic monthly charge from $8 to $8.50.

Meanwhile, an average natural gas customer using 65 therms a month would see an increase of $3.62 a month, or 5.9 percent, for a revised monthly bill of $64.81. That includes a proposed increase in the monthly basic charge from $8 to $9.

The three-member commission, which isn’t bound by the settlement agreement, will make a final decision on the utility’s rate hike request this fall.