DC Homestead

This benefit reduces your real property’s assessed value by
$71,400 [for 2016] prior to computing the yearly tax liability.

* This reduction amount usualy adjusts annualy.

The Homestead benefit is limited to residential property and to qualify:
  1. An application must be on file with the Office of Tax and Revenue;
  2. The property must be occupied by the owner/applicant and contain no more than five dwelling units (including the unit occupied by the owner); and
  3. The property must be the principal residence (domicile) of the owner/applicant.

Please file the form as soon as possible after the settlement.

NOTE: If a properly completed and approved application is filed from October 1 to March 31, the property will receive the Homestead benefit for the entire tax year [and for all tax years in the future]. If a properly completed and approved application is filed from April 1 to September 30, the property will receive one-half of the benefit reflected on the second-half tax bill [and full deductions for all tax years in the future].

Shall you need more detailed explenation please go here and here.