MWSS The oldest water system in Asia, founded as early as February 8, 1878.  Supervision and control of this system became the official responsibility of the Metropolitan Water District starting from its creation on March 6, 1919 until the enactment of Republic Act 1383 on June 18, 1955, creating a (NWSA).  RA 1383 transferred then covered by the Metropolitan Water District, along with other areas to the NWSA.
 Concessionaires Manila Water Company, Inc. (MWCI) and Maynilad Water Services, Inc. (MWSI)
 MLD Million Liters Per Day = 1000 cubic meter per day
 Service Area Metropolitan Manila, including the provinces of Rizal and Bulacan, and portions of the province of Cavite, where MWSS has jurisdiction, supervision, and control over all waterworks and sewerage systems therein
 WTP Water Treatment PlantThe Balara Treatment Plant has a full production capacity of 1,600 mld and supply more than six million people throughout the metropolis.

The La Mesa Water Treatment Plant with its least cost technological package process 2,400 mld of raw water.