In 2007, Subic Water was owner and operator of the drinking water supply schemes for Subic Bay and surrounding areas. There were raw water sources for the water treatment plant, Old Dam and New Dam. Old Dam was supplying water by gravity to treatment plant complex. The raw water from New Dam was pumped to treatment plant complex.
The blended water had mixed characteristics like high grit load, high algal load and high turbidity peaking up to 2000 NTU. The treatment plant complex consisted of old plant ( 9 mld capacity) with a Carbon steel clarifier , carbon steel gravity filters and diesel pumps for pumping the treated water. This facility was constructed way back when there was a U.S. Naval base. The new plant (19 mld capacity) consisted of a concrete Clariflocculator and concrete duel media filter beds. The Inlet works, Chemical House and Pure Water Sump were the common facilities. The rapid mix arrangement was absent from the clarifier. Out of the total design capacity of 28 mld, the plant was barely able to produce 20-22 mld treated water as the old plant had become dilapidated.