Maryland Code, State Personnel and Pensions § 22-305

(b)(1) A member who purchases service credit under this section shall:

(2) Except as provided in paragraphs (3) and (4) of this subsection, the member shall pay for service credit purchased under this section at retirement.

(3) The surviving spouse of a member of the Teachers' Retirement System may pay for the appropriate final adjustment under paragraph (3) of this subsection if:

(1) not exceeding 10 years of out-of-state public school teaching service;

(2) not exceeding 10 years for public or nonpublic school teaching service;

(3) not exceeding 5 years for postsecondary school teaching service;

(4) not exceeding 10 years of federal service or out-of-state service with a political subdivision; or

(5) as an employee of a political subdivision of the State if:

(1) not exceeding 10 years of out-of-state public school teaching service;

(2) not exceeding 10 years of public or nonpublic school teaching service;

(3) not exceeding 5 years of postsecondary school teaching service;

(4) on or before December 31, 1970, with Baltimore City as a teacher on a verified leave of absence not exceeding 2 years that is similar in all respects to leaves of absence approved by the Board of Trustees;

(5) not exceeding 10 years of federal or out-of-state municipal service; or

(6) employment as an employee of a municipal corporation of the State if the member is not otherwise entitled to receive service credit under this Division II.