Joseph P. Como, acting director of the California Public Utilities Commission's independent Division of Ratepayer Advocates, sent a letter to Edison and San Diego Gas & Electric Co. saying their customers should have their bills immediately cut.
Como said ratepayers are being charged $54 million a month to operate the plant even though it's been out of service since January.
By law, the Public Utilities Commission will have to consider lowering rates in November if the plant isn't back online. The law says ratepayer payments can be suspended if a power plant is down for nine months.
The plant's two reactors remain offline because of unexpected wear on scores of tubes that carry radioactive water. A three-month federal probe blamed a botched computer analysis for generator design flaws that ultimately resulted in heavy wear to the alloy tubing.
The Associated Press contributed to this report.