Bumbungan River originates from the Sierra Madre Mountains, in the highlands of Cavinti town, flowing through the town of Pagsanjan and ending in Lumban where it drains to Laguna de Bay, the largest lake in the country. Bumbungan is one of 21 major tributaries of the lake and responsible for up to 35% of the water that flows into the lake. It is regularly monitored by the Laguna Lake Development Authority(LLDA) through one of its 15 river monitoring stations.