Section 27-2027. Drainage of roofs and court yards

a. The owner of a
  dwelling shall grade and maintain the grading of  all  roofs,  terraces,
  shafts,  courts,  yards,  and  other  open  spaces on the lot, and shall
  provide and maintain unobstructed drainage from these areas  and  spaces
  through a drain connected to a street storm-water main or combined sewer
  and street storm-water main. In the absence of a street storm-water main
  or combined sewer and street storm-water main, the department may permit
  the storm water from such areas to drain into a street gutter leading to
  a natural channel, water course, or dry well.
    b.  The  owner  of a dwelling shall provide and maintain drainage from
  all roofs to carry off storm water, to prevent it from dripping  to  the
  ground, or from causing dampness in walls, ceilings, and open spaces.
    c.  The  department  may  require  the  owner of a dwelling to surface
  shafts, courts, yards, and other open spaces on the lot  with  concrete,
  and  to pitch the surfaces of such areas towards a sewer-connected drain
  or other adequate drainage system, except that, with respect to  private
  dwellings,  the  department  may permit the surfacing of such areas with
  bituminous aggregate or other similar material.
    d. The owner of a dwelling may plant grass,  sod,  shrubs,  trees  and
  other  vegetation  in yards and courts, unless the department orders its
  removal because in its opinion such vegetation  interferes  with  proper
  drainage, light, ventilation, or egress.