Each infrastructure improvement surcharge chargeable to each affected customer class within any single tariff of the company shall not exceed three per cent, for a sewage disposal system company, and four andone-quarter per cent, for a waterworks company, of the rates and charges applicable to the class and for the tariff in effect on the date the application was filed and, as to the allowed percentage increase, shall be uniform for each such class. The commission shall not authorize a company to have more than three infrastructure improvement surcharges for any single company tariff in effect at any time.
Additionally, the commission shall not authorize an infrastructure improvement surcharge under this section if it determines that the surcharge causes the company to earn an excessive rate of return on its valuation under section 4909.15 of the Revised Code.
As used in divisions (C)(1) and (2) of this section, "replacement of an existing plant" includes replacements that result in an upgrade or improvement of the previously existing plant, provided that the replacement plant is prudent, qualifies for recovery under this section, and performs the same or similar function or purpose as it did prior to the replacement.
R.C. § 4909.172