(BOISE) – If you’re a customer of Idaho Power, get ready for your bill to go up. Residential customers were hit with a 12.5 percent rate increase that began Saturday. According to the Idaho Public Utilities Commission, the increase was the fourth-highest power cost adjustment ever in Idaho. Average customers will see an increase of more than $11 on their bill. Idaho Power blames the increase on reduced hydroelectric revenue because of a declining water supply and the failure of Hoku in Pocatello, which meant a loss of $23 million in anticipated revenue.