In a proceeding pursuant to CPLR article 78 to compel respondents to approve a cesspool system as set forth on a certain map, petitioner appeals, as limited by its brief, from so much of a judgment of the Supreme Court, Suffolk County, dated April 22, 1975, as dismissed its petition. Judgment reversed insofar as appealed from, without costs or disbursements, and proceeding remitted to Special Term for further proceedings consistent herewith. Before a proper determination can be made in the instant proceeding, we believe that a hearing should be held with respect to the following issues: (1) whether the requirement that communal sewerage systems be constructed in all subdivisions where any plot is less than 40,000 square feet in area is unreasonable and arbitrary; (2) whether said requirement has been applied in a discrimi*607natory manner; and (3) whether sufficient expenditures were made by petitioner, in reliance upon respondents’ initial approval of its plot plans, to have acquired a vested right to an indorsement approving its plans. Martuscello, Acting P. J., Latham, Cohalan, Damiani and Titone, JJ., concur.