Metro Manila (CNN Philippines) — Maynilad Water Services, Inc. will implement rotating service interruptions in the West Zone starting September 16 (Wednesday) to help manage the water level in Angat dam during the El Niño season.

Maynilad announced on Friday (September 11) that the system adjustments will result in shortened supply schedules in 900 barangays or 56% of the West concession area in parts of North Caloocan, Valenzuela, Quezon City, Parañaque, and Cavite.

The water service interruptions will last seven hours daily.

"At this initial phase of system adjustments, we shall implement the supply interruptions daily from 9 p.m. to 4 a.m. only," Maynilad Water Supply Operations Head Engr. Ronald Padua said.

Photo: Full list of barangays affected by Maynilad water interruption

The water concessionaire planned a specific supply interruption schedule per area to ensure that affected customers will have some water supply daily, even within a limited window. This will not yet be implemented, however, during the first week as Maynilad was still limiting the service interruption during off-peak hours.

“This off-peak schedule will be gradually extended. We will adopt the different supply interruption schedules for each area,” said Padua.

The water interruption was slated to start on September 8 but was delayed because the rainfall over Ipo and La Mesa dams helped increase water level at the reservoirs.

Padua clarified that although recent rains helped maintain water elevation at Ipo Dam and augmented the reduced allocation from Angat Dam, the supply was not enough to sustain the company’s water production for the long term.

CNN Philippines' Kristine de Guzman contributed to this report.