D.C. Mun. Regs. tit. 29, § 8004
8004.1 Applicants for a certificate of domestic partnership shall provide proof of mutual residence by supplying one (1) of the following documents:
(a) A current lease or rental agreement for residential property that names both applicants as occupants of the premises named in the lease or rental agreement;
(b) A mortgage for residential property that names both applicants as mortgagors;
(c) A deed for residential property that states that both applicants share title to the premises named in the deed;
(d) Utility bills for residential property that name both persons as being responsible for payment of the utility fees for the same address; or
(e) An affidavit executed within the previous six (6) months in which the parties each state under penalty of perjury that both domestic partners share the same residence.
SOURCE: Final Rulemaking published at 49 DCR 5419 (June 14, 2002).