CITY OF MALOLOS, June 14 -- Heavy rains caused by the southwest monsoon and the onset of the rainy season on Saturday night inundated several places in Bulacan, even causing the Marilao River to overflow.

However, it failed to raise the water elevation of Angat Dam, located in Norzagaray. It is the source of 97 percent of Metro Manila's potable water.

Data from the Provincial Disaster Risk Reduction Management Office (PDRRMO) showed that the water elevation of Angat Dam as of 6 a.m. Sunday was at 167.80 meters compared to the previous day's 168.10m.

Angat's minimum operating level is 180m.

"The drop in the dam's water elevation was recorded despite the scattered heavy rain showers experienced in the different parts of Bulacan on Satur...