As used in this act, the following words and phrases shall have the meanings respectively ascribed to them herein: (a) “Municipality” means any county, city, sewer district or other public agency or any combination thereof;

(b) “Sewerage system” means sewers, mains, pumping stations, treatment works, storage facilities and all other appurtenances to the collection, storage, treatment and disposal of sewage or waste water; and

(c) “P.L. 92-500” means public law 92-500 of the 92nd session of the United States congress, cited as the “federal water pollution control act amendments of 1972.”