26 Del. C. § 301

(a) The Commission may require every public utility to file with the Commission complete schedules of every classification employed and of every individual or joint rate, fare or charge made, charged or executed by the public utility for any regulated product or service supplied or rendered within this State. Every application for a certificate of public convenience and necessity shall include a proposed tariff for approval by the Commission. A copy of all regulated tariffs then in effect shall be available for inspection by customers at each public office of the utility where applications for service are received.

(b) This section shall not apply to charges made for electric supply service or for transmission or ancillary services on and after October 1, 1999, for Delmarva Power & Light Company and April 1, 2000, for Delaware Electric Cooperative.

(c) Any person or entity in the business of a wastewater utility as of June 7, 2004, and subject to the supervision and regulation of the Commission under this chapter shall file a schedule of its rates in effect as of June 7, 2004, by November 3, 2004, in such form as the Commission may require. On July 6, 2004, such wastewater utility’s rates will be deemed in effect pending the outcome of an initial rate change request application filed in accordance with this title. Such application must be filed by January 2, 2005. A wastewater utility required to make such a rate filing may seek the assistance of the Commission in preparing its rate filing. Rates in effect on July 6, 2004, shall be deemed temporary and not subject to change, unless ordered by the Commission. Section 306 of this title shall not apply pending the outcome of this initial rate setting case. The Commission shall have 9 months to complete its review following the filing of the rate change application. However, to the extent possible, the Commission shall attempt to expedite such application. For good cause shown, the Commission may waive any provision of this subsection.

(d) Notwithstanding any other law, no public utility may assess switched access rates pursuant to tariff that are higher than the switched access rates set forth in the tariffs of the incumbent local exchange provider in the same service territory.

(e) Notwithstanding any other law, a public utility that provides telecommunications services shall not be subject to mandatory tariff or other filing requirements except with respect to switched access service.