42 U.S.C. § 3603 : US Code - Section 3603: Effective dates of certain prohibitions

    (a) Application to certain described dwellings
      Subject to the provisions of subsection (b) of this section and
    section 3607 of this title, the prohibitions against discrimination
    in the sale or rental of housing set forth in section 3604 of this
    title shall apply:
      (1) Upon enactment of this subchapter, to - 
        (A) dwellings owned or operated by the Federal Government;
        (B) dwellings provided in whole or in part with the aid of
      loans, advances, grants, or contributions made by the Federal
      Government, under agreements entered into after November 20,
      1962, unless payment due thereon has been made in full prior to
      April 11, 1968;
        (C) dwellings provided in whole or in part by loans insured,
      guaranteed, or otherwise secured by the credit of the Federal
      Government, under agreements entered into after November 20,
      1962, unless payment thereon has been made in full prior to April
      11, 1968: Provided, That nothing contained in subparagraphs (B)
      and (C) of this subsection shall be applicable to dwellings
      solely by virtue of the fact that they are subject to mortgages
      held by an FDIC or FSLIC institution; and
        (D) dwellings provided by the development or the redevelopment
      of real property purchased, rented, or otherwise obtained from a
      State or local public agency receiving Federal financial
      assistance for slum clearance or urban renewal with respect to
      such real property under loan or grant contracts entered into
      after November 20, 1962.

      (2) After December 31, 1968, to all dwellings covered by
    paragraph (1) and to all other dwellings except as exempted by
    subsection (b) of this section.
    (b) Exemptions
      Nothing in section 3604 of this title (other than subsection (c))
    shall apply to - 
        (1) any single-family house sold or rented by an owner:
      Provided, That such private individual owner does not own more
      than three such single-family houses at any one time: Provided
      further, That in the case of the sale of any such single-family
      house by a private individual owner not residing in such house at
      the time of such sale or who was not the most recent resident of
      such house prior to such sale, the exemption granted by this
      subsection shall apply only with respect to one such sale within
      any twenty-four month period: Provided further, That such bona
      fide private individual owner does not own any interest in, nor
      is there owned or reserved on his behalf, under any express or
      voluntary agreement, title to or any right to all or a portion of
      the proceeds from the sale or rental of, more than three such
      single-family houses at any one time: Provided further, That
      after December 31, 1969, the sale or rental of any such single-
      family house shall be excepted from the application of this
      subchapter only if such house is sold or rented (A) without the
      use in any manner of the sales or rental facilities or the sales
      or rental services of any real estate broker, agent, or salesman,
      or of such facilities or services of any person in the business
      of selling or renting dwellings, or of any employee or agent of
      any such broker, agent, salesman, or person and (B) without the
      publication, posting or mailing, after notice, of any
      advertisement or written notice in violation of section 3604(c)
      of this title; but nothing in this proviso shall prohibit the use
      of attorneys, escrow agents, abstractors, title companies, and
      other such professional assistance as necessary to perfect or
      transfer the title, or
        (2) rooms or units in dwellings containing living quarters
      occupied or intended to be occupied by no more than four families
      living independently of each other, if the owner actually
      maintains and occupies one of such living quarters as his
      residence.
    (c) Business of selling or renting dwellings defined
      For the purposes of subsection (b) of this section, a person
    shall be deemed to be in the business of selling or renting
    dwellings if - 
        (1) he has, within the preceding twelve months, participated as
      principal in three or more transactions involving the sale or
      rental of any dwelling or any interest therein, or
        (2) he has, within the preceding twelve months, participated as
      agent, other than in the sale of his own personal residence in
      providing sales or rental facilities or sales or rental services
      in two or more transactions involving the sale or rental of any
      dwelling or any interest therein, or
        (3) he is the owner of any dwelling designed or intended for
      occupancy by, or occupied by, five or more families.