Toei Tamagawa Ni-chome Apartments 都営多摩川二丁目第２アパート (map) is a pair of buildings (#19 an #21) in Ota-ku, not far from the Tamagawa river.
Building 21, and its rooftop water tank 高架水槽 (elevated tank)
The danchi is adjacent to a small park, Furukawa Daini Jido Park 古川第二児童公園, seen here with its very public bathroom:
Around the corner is a delightful old fruit store.
I’ve found that fruit stores are consistently the most atmospheric old buildings in Tokyo, for instance: