Section 11-2103. Presumptions and burden of proof

For the purpose of the
  proper administration of this chapter and to prevent evasion of the  tax
  hereby  imposed,  it  shall  be presumed that all deeds and transfers of
  economic interests in real property are taxable. Where the consideration
  includes property other than  money,  it  shall  be  presumed  that  the
  consideration  is  the  value  of the real property or interest therein.
  Such presumptions shall prevail until the contrary  is  established  and
  the  burden of proving the contrary shall be on the taxpayer. The burden
  of proving that a lien or encumbrance existed on the  real  property  or
  interest  therein  before  the delivery of the deed and remained thereon
  thereafter and the  burden  of  proving  the  amount  of  such  lien  or
  encumbrance  at  the  time  of  the delivery of the deed shall be on the
  taxpayer.