If the board of supervisors of each of two or more contiguous counties by resolution declares that there is a need for one housing authority to be created for all of such counties to exercise in such counties powers and other functions prescribed for a regional housing authority, a political subdivision of the Commonwealth to be known as a regional housing authority shall thereupon exist for all of such counties and exercise its public and corporate powers and other functions in such counties; and thereupon each housing authority created for each of such counties shall cease to exist except for the purpose of winding up its affairs and executing a deed to the regional housing authority as hereinafter provided; provided that the board of supervisors of a county shall not adopt a resolution as aforesaid if there is a county housing authority created for such county which has any obligations outstanding unless first, all obligees of such county housing authority and parties to the contracts, bonds, notes, and other obligations of such county housing authority consent in writing to the substitution of such regional housing authority in lieu of such county housing authority on all such contracts, bonds, notes, or other obligations; and second, the commissioners of such county housing authority adopt a resolution consenting to the transfer of all the rights, contracts, obligations, and property, real and personal, of such county housing authority to such regional housing authority as hereinafter provided; and provided further that when the above two conditions are complied with and such regional housing authority is created and authorized to exercise its powers and other functions, all rights, contracts, agreements, obligations, and property of such county housing authority shall be in the name of and vest in such regional housing authority, and all obligations of such county housing authority shall be the obligations of such regional housing authority and all rights and remedies of any person against such county housing authority may be asserted, enforced, and prosecuted against such regional housing authority to the same extent as they might have been asserted, enforced, and prosecuted against such county housing authority. When any real property of a county housing authority vests in a regional housing authority as provided above, the county housing authority shall execute a deed of such property to the regional housing authority which thereupon shall file such deed in the office provided for the filing of deeds, provided that nothing contained in this sentence shall affect the vesting of property in the regional housing authority as provided above. The board of supervisors of each of two or more contiguous counties shall by resolution declare that there is a need for one regional housing authority to be created for all of such counties to exercise in such counties powers and other functions prescribed for a regional housing authority, if such board of supervisors finds (and only if it finds) (a) that insanitary or unsafe inhabited dwelling accommodations exist in such county or there is a shortage of safe or sanitary dwelling accommodations in such county available to persons of low income at rentals they can afford and (b) that a regional housing authority would be a more efficient or economical administrative unit than the housing authority of such county to carry out the purposes of this Housing Authorities Law in such county. In any suit, action, or proceeding involving the validity or enforcement of or relating to any contract of the regional housing authority, the regional housing authority shall be conclusively deemed to have become created as a public body corporate and politic and to have become established and authorized to transact business and exercise its powers hereunder upon proof of the adoption of a resolution by the board of supervisors of each of the counties creating the regional housing authority declaring the need for the regional housing authority. Each such resolution shall be deemed sufficient if it declares that there is need for the regional housing authority and finds in substantially the foregoing terms (no further detail being necessary) that the conditions enumerated above in (a) and (b) exist. A copy of such resolution of the board of supervisors of a county, duly certified by the clerk of such county, shall be admissible in evidence in any suit, action, or proceeding. The area of operation of a regional housing authority shall include (except as otherwise provided elsewhere in this chapter) all of the counties for which such regional housing authority is created and established.