No employer shall discriminate within any establishment between employees on the basis of sex by paying wages to employees in such establishment, a rate less than the rate at which he or she pays wages to employees of the opposite sex in such establishment for equal work on jobs of the performance of which requires equal skill, effort and responsibility, and which are performed under similar working conditions, except where such payment is made pursuant to:

    1.    A seniority system;

    2.    A merit system;

    3.    A system which measures earnings by quantity or quality of production; or

    4.    A diffential based on any other factor other than sex.

    B.    An employer who is paying a wage rate diffential in violation of the above shall not, in order to comply with this provision, reduce the wage rate of any other employee. (Ord. 92-45 (part), 1992; prior code § 12-7)