A landlord and tenant may agree, in writing, to exempt themselves from the provisions of RCW 59.18.060, 59.18.100, 59.18.110, 59.18.120, 59.18.130, and 59.18.190 if the following conditions have been met:
(1) The agreement may not appear in a standard form lease or rental agreement;
(2) There is no substantial inequality in the bargaining position of the two parties;
(3) The exemption does not violate the public policy of this state in favor of the ensuring safe, and sanitary housing; and
(4) Either the local county prosecutor's office or the consumer protection division of the attorney general's office or the attorney for the tenant has approved in writing the application for exemption as complying with subsections (1) through (3) of this section.