Manila Water Co., Inc., the East Zone concessionaire of Metro Manila, is aiming to finish by yearend the replacement of its decades-old San Juan reservoir, a project intended to strengthen water storage capacity for communities across the metropolitan area.

In a statement issued Monday, the water service provider said the P970-million San Juan reservoir was 84% complete as of July. Once finished, the facility will be able to store up to 56 million liters of water.

The new reservoir will replace the original structure, which was built in 1968. It is designed to withstand major earthquakes and to support reliable water service. According to Manila Water, the facility incorporates upgraded structural, electrical, instrumentation, and mechanical systems intended to help maintain service amid environmental and seismic risks.

The decision to replace the reservoir followed structural assessments of the existing facility. Citing engineering studies conducted by DCCD Engineering Corp. in 2011 and 2016, Manila Water said the reservoir's roof slab and walls had significantly deteriorated after decades of service.

The company said the studies also indicated a high risk of structural failure during major seismic events, including a potential magnitude-7.2 earthquake. That scenario is consistent with preparedness concerns raised in the Philippines, which sits along the Pacific Ring of Fire; government agencies have long cited the possibility of a major tremor from the Valley Fault System affecting Metro Manila, often referred to as "The Big One."

Manila Water noted that the reservoir's top slab had undergone several repairs over the years to address holes and other defects that could affect the quality and safety of water supplied to the San Juan Pumping Station. Reservoir storage of this kind plays a role in cushioning supply during interruptions, as Metro Manila's water service has in past years been disrupted by shortages — notably the 2019 service crisis when declining levels at Angat Dam, the metropolis' main raw water source, forced rotational service cuts across the concession areas.

"The project forms part of Manila Water's continuing investments to modernize and future-proof its water infrastructure amid growing challenges posed by urbanization, extreme weather events, and natural disasters," the company said.

Manila Water serves the east zone of Metro Manila, an area that covers parts of Marikina, Pasig, Makati, Taguig, Pateros, Mandaluyong, and San Juan, portions of Quezon City and Manila, and several towns in Rizal province. — Sheldeen Joy Talavera