Retail natural gas rates in Washington state are decreasing at two of the state’s major utility distribution companies, following actions Thursday by state regulators. Two other gas providers will have slight increases.

It is another reflection of the generally low gas commodity prices from the two major supply basins covering the state — western Canada and the U.S. Rockies (Wyoming), the Utilities and Transportation Commission (UTC) noted in making the separate rate decisions for Avista Utilities, NW Natural, Puget Sound Energy (PSE), and Cascade Natural Gas Co.

“The variation in rates among the three gas utilities is due in part to differences in monthly residential usage, conservation, and energy efficiency programs, low-income program costs, and gas purchasing practices,” a UTC spokesperson said.

Two of the utilities — PSE and Cascade — have UTC-approved pipeline replacement programs that add to the annual purchased gas cost adjustment (PGA) filings. The two decreases ranged from 1.5% to 4.9%; the increases were 0.2% to 1.3%.

Spokane, WA-based Avista will lower its rates 4.9% for its 155,000 customers in the eastern part of the state, effective Tuesday (Nov. 1). Portland, OR-based NW Natural will drop its rates 1.5% for its 75,000 gas utility customers in three counties across the Columbia River from Portland in Washington.

In the western part of the state, PSE’s rates will stay essentially flat (0.2% increase) for its more than 800,000 customers in six counties, including the Seattle-Tacoma metropolitan area. MDU Resources Group’s Kennewick, WA-based Cascade Natural will increase its rates by 1.3% for its 210,000 customers spread throughout parts of central Washington.

With the rate changes the average monthly gas utility bills will range from $71.60 for PSE customers to $42.25 for Cascade, with customers of each utility using different average monthly volumes of gas ranging from 68 therms (PSE) to 49 therms (Cascade).