This is a tsukubai (stone basin) located at Ryōan-ji Temple, a Zen Buddhist temple in the northwest of Kyoto City.
A tsukubai is a stone basin filled with water used to purify one’s hands
and mouth before entering a tearoom.
The inscription here reads “吾唯足知,” which translates to “I learn only to be contented” or “I am content with what I have (am)” in English. This is a Zen teaching. 
Ryoan-ji Temple
Location