Utah Code Title 54. Public Utilities § 54-4-24. Depreciation accounts and fund

The commission shall have power to require any or all public utilities to carry a proper and adequate depreciation account in accordance with such rules, regulations and forms of account as the commission may prescribe. The commission may from time to time ascertain, determine and, by order, fix the proper and adequate rates of depreciation of the several classes of property of each public utility. Each public utility shall conform its depreciation accounts to the rates so ascertained, determined and fixed, and shall set aside the money so provided for out of earnings and carry the same in a depreciation fund and expend such fund only for such purposes and under such rules and regulations, both as to original expenditure and subsequent replacement, as the commission may prescribe. The income upon investments of money in such fund shall likewise be carried in such fund.