MANILA -- Angat Dam, the main water source of Metro Manila, may dip to its lowest ever level this week, regulators said Wednesday.

Recent rains brought by the habagat or southwest monsoon have not eased the dam's water level, which was at the 158.40-meter mark as of 6 a.m., said National Water Resources Board Executive Director Sevillo David Jr.

This figure is below Angat Dam's 160-meter critical level, and is just slightly above the current record-low of 157.56-meter level that was recorded in July 2010, when an El Niño phenomenon characterized by lack of rains gripped the country.

"Kung magpapatuloy po ito at wala pong mga pag-ulan na darating sa mga susunod na araw, sa tantya po natin, bago magtapos ang linggo, baka malampasan po iyung record na pinakamababang naitala po noong 2010," David told radio DZMM.

(If this continues and there would be no rains in the next days, we estimate that before the week ends, we will breach the record-low registered in 2010.)

Watch more in iWantv or TFC.tv

Water supply in Metro Manila was slashed to 36 cubic meters per second from 40 m³/s last weekend due to the dam's declining level, the NWRB said. Some areas have since experienced rotational water supply outages.

Last March, the dam's declining water level, lack of rains due to El Niño, and high demand were blamed for a water supply shortage that brought misery to more than a million households in Metro Manila.

In a House hearing Tuesday, Local Water Utilities Administration acting chief Jeci Lapus said Metro Manila's water concessionaires may seek additional water supply from nearby provinces like Laguna, Bulacan and Cavite.

There is no agreement yet on how the proposal could be carried out, said NWRB's David.

Monsoon rains on Wednesday will prevail over parts of Central Luzon, where Angat Dam is located, state weather bureau PAGASA said.

• PAGASA: Rains to persist after Dodong's exit