SM City Masinag: An engineering marvel

SM City Masinag in Antipolo City was intentionally built in a historically flood-prone area to serve as a buffer for runoff flowing down from upper watersheds.

The city sits along the western foothills of the Sierra Madre, where rainfall drains through several rivers and creeks. Masinag lies in one of these downstream pathways. As urbanization has expanded across Antipolo, paved roads, roofs, parking areas, and other impervious surfaces reduce the ground’s ability to absorb rain. More rainfall therefore becomes surface runoff, increasing the volume and speed of water flowing into streets and drainage networks. During a severe downpour, drainage systems can be overwhelmed before the water can reach larger receiving waterways.

The mall that opened in 2011 was built with an underground rainwater catchment basin that can hold 17,681 cubic meters of runoff — more than seven Olympic-sized swimming pools. Without the underground reservoir, that amount of excess rainwater would flood streets and nearby communities.

After collecting the runoff, powerful submersible pumps releases or manages it after the immediate flood risk has passed. During super typhoon “Carina” (“Gaemi”) in July 2024, the catchment basin collected 8,653 cubic meters of rainwater.

Later, SM Supermalls and the SM Engineering Design and Development Corp. (SMEDDC), a subsidiary of SM Prime Holdings Inc. that manages the design, construction and maintenance of SM properties, added a rainwater treatment facility (RTF) to SM City Masinag so the collected runoff could be converted to potable water.

On 29 October 2026, the RTF was formally launched.

“The SM City Masinag Rainwater Treatment Facility is the first facility of this kind in the city of Antipolo, and the second Rainwater Treatment Facility in all SM Supermalls,” Engr. Liza Silerio, vice president for corporate compliance group for SM Supermalls and program director for SM environment and sustainability, said at the launching ceremony.

“This initiative is in line with our continued promise to take care of the environment and to improve the quality of our waterways for the benefit of our community.”

Engr. Alford Marion Ronduen, operations head and vice president at SMEDDC, said one-third of the SM City Masinag’s annual water consumption — 23,000 cubic meters — can be provided by the RTF.

“On a daily basis, this facility can produce 200 cubic meters (200,000 liters) of potable water. Just to give you an idea, the daily consumption of the mall is around 350 to 370 cubic meters,” Ronduen said, adding that the water is cleaned through filtration, disinfection and reverse osmosis.

Quality-control and laboratory personnel conduct routine testing through a six-step purification process to ensure that safety and chemical-balance standards are met before redistribution.

Joe Amil Salino, regional director of the Environmental Management Bureau under the Department of Environment and Natural Resources, graced the launching of the RTF and found the RTF very interesting.

“We are experiencing El Niño now and that would last until 2027. It’s good that we’re conserving water,” he said. “We have to store and harvest water for the dry season.”

Silerio said the RTF is a product of SM Group’s culture of prioritizing preparedness.

“We have been preparing for a long time. And we have already done a lot in terms of our preparation,” she said.

SM City Masinag shows how private infrastructure can complement public flood-control efforts. Its underground catchment basin addresses the immediate problem of runoff accumulation, while the RTF extends the benefit into the dry season by recovering and purifying water that would otherwise go unused.