Md. Code, Real Prop. § 8-209

(a) (1) This section applies only to a residential lease. (2) This section does not apply to a landlord who has provided written notice of the intent to terminate a tenancy in accordance with § 8–402(c)(2) of this article. (b) (1) A landlord shall notify a tenant in writing before increasing the tenant’s rent. (2) (i) The notice required under paragraph (1) of this subsection shall: 1. Be sent by first–class mail with a certificate of mailing; or 2. If elected by the tenant, sent by electronic delivery in at least one of the following forms: A. An e–mail message; B. A text message; or C. Through an electronic tenant portal. (ii) The electronic delivery method shall provide the landlord with proof of transmission of the notice. (iii) A landlord may not condition the acceptance of a lease application on the tenant’s election to receive notice under this subsection by electronic delivery. (3) A landlord shall provide the notice required under paragraph (1) of this subsection: (i) For tenancies for a term of more than 1 month, at least 90 days in advance of the rent increase; (ii) For tenancies for a term of more than 1 week, but not more than 1 month, at least 60 days in advance of the rent increase; and (iii) For tenancies for a term of 1 week or less: 1. At least 7 days in advance of the rent increase if the parties have a written lease; or 2. At least 21 days in advance of the rent increase if the parties do not have a written lease. (c) This section does not affect or supersede any local law or ordinance that requires additional notice or provides additional tenant protections.