San Cristobal River
The San Cristobal River, also known as the Matang Tubig River, is in Laguna province, Philippines. It flows through the cities of Calamba and Cabuyao.
It is one of 21 major tributaries of Laguna de Bay, the big lake near Manila. The river starts from Mount Sungay, the highest mountain in Cavite, and drains the northern and eastern sides of the mountain. Its watershed includes Calamba and Cabuyao in Laguna, and Tagaytay and Silang in Cavite.
The San Cristobal River connects with Matang Tubig in Casile and Canlubang. Along with the San Juan River, it helps drain Calamba’s and Cabuyao’s rainwater and wastewater into Laguna de Bay.
Pollution is a major problem. The rivers are heavily polluted, which worsens the water quality of Laguna de Bay. The Laguna Lake Development Authority (LLDA) says San Cristobal is a significant source of nutrient pollution for the lake.
To protect Laguna de Bay, the LLDA has created river basin councils and conservation programs. The San Cristobal River is supported by groups like SACRED (San Cristobal River Enhancement Defenders), which work to conserve the river.
This page was last edited on 2 February 2026, at 20:59 (CET).