Manila Water Co., the private concessionaire for Metro Manila’s east zone, is accelerating the diversification of its supply network as the end of the northeast monsoon signals a seasonal surge in consumption in its service area.

In a statement, Manila Water said the utility, which serves approximately 7.8 million customers, is ramping up drawdowns from alternative sources to reduce its historical dependence on the Angat Dam.

The strategy centers on the Wawa–Calawis system, a critical infrastructure cluster designed to insulate the capital’s eastern corridor from potential shortages during the peak summer months.

Central to this expansion are the Upper Wawa Dam and the Tayabasan Weir, both developed and operated by WawaJVCo.

Manila Water consolidated its control over these assets last year through a ₱37.8 billion acquisition of the project company. At peak capacity, these facilities are engineered to provide up to 710 million liters per day (MLD), creating a substantial buffer for the franchise area.

The company is also integrating output from the ₱8.2 billion Calawis water supply system. That project is anchored by an 80 MLD treatment plant currently supplying Antipolo City and neighboring municipalities in Rizal province.

By linking these disparate sources, the company aims to create a more resilient grid that can shift loads depending on localized demand and raw water availability.

Beyond the Wawa system, Manila Water continues to tap Laguna Lake through its Cardona treatment plant. The facility currently contributes 100 MLD of treated water to roughly 800,000 consumers.

The company confirmed that the asset is undergoing technical upgrades intended to optimize its filtration processes and stabilize discharge rates during periods of fluctuating lake water quality.

The push for supply redundancy comes as the Philippines enters the dry season, a period typically characterized by increased household usage and lower reservoir inflows. Historically, the East Zone has relied heavily on the aging Angat Dam, which also supplies the West Zone and irrigation for nearby provinces.

"By securing and developing alternative raw water sources, we are better positioned to maintain reliable service, manage seasonal demand shifts, and support overall system stability," said Jeric Sevilla, Manila Water’s corporate communications director. The company maintains that these investments are essential to decoupling the region’s economic growth from its reliance on a single primary water source.