On 24 November 2020, the MWSS Regulatory Office (RO) Technical Regulation Area (TRA) conducted an investigation on the operations of Maynilad Water Services, Inc. and the water quality at the La Mesa Treatment Plants (LMTPs) 1 & 2.

The said investigation aimed to assess the impact of Typhoon Ulysses on Maynilad’s water production. Specifically, it sought to validate the reasons behind the decrease in water production; survey desludging of the basins; and examine the raw and treated water quality at the LMTPs.