Md. Code, Public Utilities § 25–402

(a) In addition to any other charges authorized under this division, the Commission may impose a system development charge that shall be paid by an applicant for new service.

(b) The system development charge shall be paid as follows:

(1) for residential properties:

(i) 50% at the time the plumbing permit application is filed; and

(ii) 50% within 12 months after the earlier of the date on which a plumbing permit application is filed or on transfer of title to the property; and

(2) for other properties, 100% at the time the plumbing permit application is filed.

(c) When the applicant files the plumbing permit application, the applicant shall deposit with the Commission security:

(1) in the form of an irrevocable letter of credit;

(2) in the form of a financial guaranty bond; or

(3) in a form the Commission establishes and approves under its regulations.