Public Utilities Code § 1351
CHAPTER 7. Valuation of Public Utility Properties
The commission may ascertain for each purpose specified in this part, the value of the property of every public utility in this State and every fact and element of value which in its judgment may or does have any bearing on such value. The commission may make revaluations from time to time and ascertain the value of all additions, betterments, extensions, and new construction to the property of every public utility.