Avista is seeking to raise the price of electricity and natural gas through a series of rate filings.

For the average Avista ratepayer in Eastern Washington, the request amounts to adding $10.62 to a homeowner’s monthly electric bill and another $4 a month for natural gas.

In Idaho the request would add $11.40 to the average homeowner’s electric bill and an extra $2.77 a month for natural gas.

The Spokane-based utility said the extra money is needed to pay for improvements to its dams, transmission systems, and network of neighborhood distribution lines, along with locking in new long-term contracts with outside electricity providers to meet the needs of a growing population.

The company filed its requests with regulators in each state Tuesday. Specifically, Avista seeks a 13.4 percent rate hike for electricity and 6 percent more from its natural gas customers in Washington; and a 13.1 percent electric rate increase and 4.1 percent increase for natural gas in Idaho.