During the Azuchi – Momoyama period ( 1568 to 1600 ) , the " Taiko Sewerage " was built around Osaka Castle , and it still exists and functions today . The use of modern sewage systems began in 1884 , with the installation of the first brick and ceramic sewer in Kanda , Tokyo . More plumbing and sewage systems were installed after the Great Kantō earthquake to avoid diseases after future earthquakes . However , the construction of sewers increased only after World War II to cope with the waste products of the growing population centers . By the year 2000 , 60 % of the population was connected to a sewer system . The national Sewage Day is September 10
Great Kantō earthquake
1923 Great Kantō earthquake
Toilets in Japan