Del. Code Ann. tit. 26, § 316
(b) A public utility shall not recover the following costs from its customers, whether as part of proposed base rate costs, a rider, or other charges:
(5) Advertising and public relations expenses that do not directly relate to a purpose or program that is required or authorized under statute or commission rule or order.
a. Advertising and public relations expenses for which cost recovery is prohibited include:
c. “Advertising” does not include: