Good news, Treasure Valley utility customers: Your bills will go down. Here's why.

An Idaho Power meter.
An Idaho Power meter.

Treasure Valley residents, your utility bills are about to get lower.

Idaho Power customers will see rate drops of just over 7 percent, Suez Water Idaho customers 5.6 percent and Intermountain Gas customers 2.6 percent.

The reason? Federal and state corporate-tax cuts. And in the case of Idaho Power, the latest fluctuations in routine annual cost adjustments.

The Idaho Public Utilities Commission announced the rate decreases Friday. They are retroactive to June 1.

Typical residential customers are expected to see a $7.04 decrease in their monthly power bills and a $0.015 drop per therm in their gas bills, the PUC said. The commission did not say how much a typical water bill would fall.

On Jan. 1, 2018, federal corporate tax rates dropped from 35 percent to 21 percent as a part of the Tax Cuts and Jobs Act. On March 1, Gov. Butch Otter signed a bill that also cut Idaho's corporate tax rate to 6.925 percent, down from 7.4 percent.

Idaho Power's rates also fell because of the fixed-cost adjustment (FCA) and power-cost adjustment (PCA), a pair of annual cost adjustments based on consumer energy use and power supply costs, respectively.

Michael Katz: 208-377-6444