Section 27-2095. Service of notices and orders

a. Except as otherwise
  expressly provided in this  code,  any  notice  of  violation  or  other
  notice,  or  any  order  authorized  or  required  to  be  served by the
  department under the provisions of this code, shall  be  served  in  the
  following  manner  on  any  person  or corporation to whom or which such
  notice or order is directed:
    (1) By delivering a copy of  such  notice  or  order  to  such  person
  directly,  or  if  it is directed to a corporation, by delivering a copy
  thereof to any officer or managing agent of such corporation personally;
  or
    (2) By delivering a copy of such notice or  order  to  any  person  of
  suitable age and discretion at the residence or place of business of the
  person to whom it is directed, or if it is directed to a corporation, at
  any office of such corporation; or
    (3) (i) If service is to be made on an owner of a dwelling, by mailing
  a  copy  of  such  notice  or  order to the latest business or residence
  address of such owner as set forth in any registration  statement  filed
  by  such  owner  with  the department under the applicable provisions of
  article two of this subchapter;
    (ii) If service is to be made on a managing agent of any such dwelling
  designated under the  applicable  provisions  of  article  two  of  this
  subchapter,  by  mailing  a  copy  thereof  to  the  latest  business or
  residence  address  of  such  managing  agent  set  forth  in  any  such
  registration  statement  or  designation  filed  by  the  owner  of such
  dwelling;
    (iii) If service is to be made on an owner of a dwelling who  has  not
  filed  such a registration statement in relation to such dwelling, or on
  a managing agent of any such dwelling who has not been designated  under
  the  applicable provisions of article two of this subchapter, by posting
  a copy of such notice or order in a conspicuous place in such  dwelling,
  or  by  delivering  a  copy  thereof  to  any person of suitable age and
  discretion in charge of or apparently in charge of such dwelling, or  by
  mailing a copy thereof to such owner or managing agent at the last known
  business or residence address of such owner or managing agent.
    b. Any such notice directed to an owner of a dwelling or tenant of any
  space therein need not designate such owner or tenant by name, but shall
  refer  to  such  dwelling  or  space  by  a  description  which shall be
  sufficient to identify same and shall state that it is directed  to  the
  owner of such dwelling or tenant of such space, as the case may be.
    c.  Where  a  designation  of  a  managing  agent under the applicable
  provisions of article two of this subchapter is currently in  effect  as
  to  any multiple dwelling, any notice mentioned in subdivision a of this
  section which is directed to the owner of such multiple  dwelling  shall
  also  be  directed  to  such  managing agent, and shall be served by the
  department on both such owner and managing agent.
    d. If a  mortgagee  or  lienor  has  registered  with  the  department
  pursuant  to  the  provisions  of section 27-2109 of article two of this
  subchapter, any notice of  violation  or  other  notice,  or  any  order
  authorized  or  required  to  be  served  by  the  department  under the
  provisions of this code on the owner of a dwelling may also be mailed to
  such mortgagee or lienor no later than five days  after  the  date  upon
  which   such  notice  or  order  is  served  upon  the  owner,  but  the
  department's failure to mail such notice or order to such  mortgagee  or
  lienor  shall  not  in  any  way  affect the validity of service of such
  notice or order upon the owner.