Puget Sound Energy‘s natural gas rates will rise about 10 percent beginning today, adding an estimated $8.49 to the monthly bills of residential ratepayers.

The utility (PSE) said the rate increase, approved by the state Utilities and Transportation Commission, reflect rising wholesale prices of natural gas.

The average bill for a typical residential ratepayer using 68 therms of natural gas will rise by 10.4 percent, or $8.49 a month, to $90.61, according to the commission.

The increase brings natural gas rates to about the same level PSE customers paid two years ago, the commission stated.

PSE has more than 737,000 natural-gas customers in King County and parts of five other counties.

Natural-gas utilities in Washington aren’t allowed to earn a profit on gas-commodity increases, commission officials noted.

The three-member commission is the state regulatory agency for private, investor-owned utilities in Washington. The commission monitors utilities’ service to customers and reviews their rates, while allowing the companies to earn a fair profit.