Maryland Code, Environment § 4-201.1

(1) Optimizing conservation of natural features, such as drainage patterns, soils, and vegetation;

(2) Minimizing use of impervious surfaces;

(3) Slowing down runoff to maintain discharge timing and to increase infiltration and evapotranspiration; and

(4) Using other nonstructural practices or innovative stormwater management technologies approved by the Department.

(d)(1) “Impervious surface” means a surface that does not allow stormwater to infiltrate into the ground.

(2) “Impervious surface” includes rooftops, driveways, sidewalks, or pavement.