Nearly half of the lake's depth has a shallow depression at the bottom, indicating its volcanic origin.

The lake is behind San Pablo city hall and is dotted with fishpens and small cottages built on stilts.

A giant sampaloc (Tamarindus indica or tamarind tree) once grew in the garden of a selfish, stingy old woman.

After the diwata (still appearing as the old man) had departed, there was a thundering noise and rain, followed by the cracking of the earth.

The entire orchard sank into a colossal pit which was immediately filled with water, which villagers thence named after the large tamarind tree.