The two Metro Manila water concessionaires announced on Tuesday there will be water service interruptions after the National Water Resources Board (NWRB) reduced raw water allocation for the Metropolitan Waterworks and Sewerage System (MWSS).

From the standard 46 cubic meters per second, water allocation coming from the Angat Dam will be reduced to 40 cubic meters per second, NWRB said in a statement.

This is due to the continuous decline in water elevation of the dam despite the onset of rainy season.

In separate official statements, Manila Water and Maynilad said they will implement rotational service interruptions in their concession areas.

Manila Water said service interruption will affect not only the East Zone concession area but the entire Metro Manila.

"We are constrained to implement a new scheme of rotational water service interruptions...for about 8 to 12 hours during night time," Manila Water said.

Maynilad assured their customers in the affected concession areas they will administer operational measures to ease the impact of reduced water supply.

"Maynilad has measures in place...including the extension of operating hours of our pumping stations and reactivation of deep wells, among others," Maynilad said.

"If necessary, Maynilad will send out mobile water tankers and install static water tanks for severely affected areas," it added.

Both water service providers are expected to announce the list of areas affected and the supply availability schedules in their websites and social media platforms.

As of Tuesday morning, the Philippine Atmospheric Geophysical and Astronomical Services Administration (Pagasa) reported that Angat Dam's water level is at 161.78. This is 18.22 meters off from the dam's minimum operating water level of 180 meters. Cristina Eloisa Baclig/DMS