DENR CENRO Lipa, together with the Provincial Government - Environment and Natural Resources Office (PG-ENRO), conducted water sampling activity in three (3) water sampling stations located in Brgy. San Lucas, Lipa City (upstream), Brgy. Darasa, Tanauan City (midstream) and Brgy. Sta. Anastacia, Sto. Tomas City (downstream).

Water quality monitoring of San Juan River System is one of the implementing activities of Manila Bay Rehabilitation Program.