Avista’s Idaho customers could see a 6.6 percent hike in their electric bills by Oct. 1, along with a corresponding 1.9 percent hike in natural gas rates. The Spokane-based utility has reached a proposed rate settlement with the Idaho Public Utilities Commission staff, several of its large customers and Community Action Partnership Association, which provides utility assistance to low-income families. The settlement must still be reviewed by the three-member Public Utilities Commission, which has the final say on setting rates. If approved, electric bills for residential customers using 1,000 kilowatts of electricity each month would increase by $5.37 to $86.27. Natural gas customers using 65 therms of gas each month would see their monthly bill increase by $1.71 to $59.40.