This stone filtration facility is believed to have been built in 1907, ahead of a visit by then Crown Prince and later Emperor Taishō.

Spring water from the hillside above Sengan-en was brought here through stone pipes, filtered underground through layers of sand, and then supplied to the Shimazu residence and surrounding buildings.

Stone structures are rare in Japan, but Kagoshima has abundant volcanic stone that is easy to work with. Even so, filtration facilities made entirely of stone, including the roof, are extremely uncommon.

Because of this, the Filtration Pond was designated a National Tangible Cultural Property in 2001.