Md. Code, Environment § 9–217

Notwithstanding any provision of this title or any regulation of the Department that prohibits the installation of a specific on-site sewage disposal system, at the request of a person who owns a lot that was legally established on November 17, 1985, the Department shall test and evaluate the lot for an on-site sewage disposal system as if the person had applied to the Department and the Department had acted on the application on November 17, 1985.