Md. Code, Pub. Util. § 25-101

(a) In this section, “industrial user” means: (1) an industry identified in the category “Division D – Manufacturing” of the North American Industry Classification System developed by the United States Office of Management and Budget; or (2) any industry in another class of significant waste producers that the Commission establishes by regulation. (b) Notwithstanding any other provision of this subtitle or Subtitles 3 through 5 of this title that requires a regulation, rate, or charge to be uniform throughout the sanitary district, if the Commission determines that in any area of the sanitary district the conditions for service from any of its systems, including the cost of instituting and maintaining the service, are substantially different from the conditions for service generally in the sanitary district, the Commission may define the area as a subdistrict and adopt a different regulation, rate, or charge to apply in that subdistrict. (c) Notwithstanding any other provision of this subtitle or Subtitles 3 through 5 of this title that requires a regulation, rate, or charge to be uniform throughout the sanitary district, if the Commission determines that conditions for service from any of its systems, including the cost of maintaining and operating the systems, to a property occupied by an industrial user are substantially different from the conditions for service generally in the sanitary district, the Commission may adopt regulations and set higher rates or charges or adopt more restrictive usage regulations for industrial users. (d) Before adopting any different regulation, rate, or charge under this section, the Commission shall: (1) publish notice of the proposed modification in at least one newspaper of general circulation in each county of the sanitary district; and (2) hold a public hearing on the necessity or advisability of a modification of the regulation, rate, or charge.