Tissa Wewa is a reservoir in Tissamaharama, thought to have been constructed in the 3rd century BC, either by Mahanaga of Ruhuna or his successor Yatala Tissa of Ruhuna, in order to irrigate paddy lands and supply water to the flourishing city of Tissamaharama.

The lake was restored in 1871. The embankment (or bund) on the southern shore supports the Tissa-Kataragama road (B464), which is lined by old Indian rain trees planted by the British to provide shade.

The centrepiece of the town and its surrounds is the lovely Tissa Wewa (Tissa Tank), a huge artificial lake. In the evening, check out the flocks of egrets that descend onto the trees around the lake to roost. The road along the southern edge has a wide Lakeside Walkway for strolling. Don't be tempted to swim here as crocodiles are sometimes spotted.