Based on the report of the Metro Manila Drinking Water Quality Monitoring Committee (MMDWQMC) the "drinking water in the Metro Manila Waterworks and Sewerage System (MWSS) distribution system for the the month of May was "of sanitary quality with adequate residual chlorine."
The MWSS oversees water being supplied by concessionaires Maynilad Water Services Inc. (Maynilad) and the Manila Water Company Inc. (MWCI).
"The average residual chlorine is 0.65 ppm for the East Service Area and 0.85 for the West Service Area," the report showed.
This is way above the requirement of the Philippine National Standardized Drinking Water (PNSDW) of at least 0.2 ppm residual chlorine from the farthest point of the distribution.
The committee also found out that the physical and chemical characteristics of the water such as pH or hydrogen ion concentrate, color, taste, odor, turbidity, chloride, iron, hardness, total dissolved solids, sulfate, fluoride, calcium and magnesium met the PNSDW requirements.
The committee is composed of the Department of Health (DOH) reference laboratories in Makati, Marikina, Pasay, Parañaque Quezon City, Las Piñas, Ayala Water Works, Maynilad, MWCI and MWSS.
According to Engineer Nilo Marayag, DOH environmental engineer for Metro Manila, the committee has 1,200 sampling points all over the metropolis where water specimens are being collected every month. Marayag said that water supply is usually of good quality when released from the distribution system.
The water supply, however, gets contaminated at the household level because of illegal tapping and leaking water pipes. He added that the public could help the government ensure potable water supply by reporting water thieves and leaking pipes to authorities.