The Bathhouse is a very grandiose and opulent structure in the Spirit Realm. Built in a traditional Japanese bathhouse style, its color scheme encompasses shades of red, green and semi-dark tones of brown. A waterfall is also present at its bridge crossing. Early in the series, it is established that the bathhouse has a set of old, unstable side stairs that lead directly into Kamajī's Boiler Room, bypassing the usual method of arriving by the internal elevators.
Aside from the bridge, waterfall, entrance and side stairs, the Bathhouse has multiple side entrances and back doors that can be used to dump water outside without being seen by the customers. Haku takes Chihiro through one of these backyard routes and instructs her to enter through the Boiler Room via the side stairs to meet Kamaji.
The Bathhouse is a structure with multiple floors. The floors above ground level are numbered in a special manner that incorporates use of the words "天", literally meaning "heaven" and "地", literally meaning "ground". The floors below ground are not given names in the film. It is shown in the film that the Bathhouse does have working, one-way elevators that travel to some of the floors if not all the floors by the pull of a lever.
The workers are also assigned to quarters in the bathhouse (most likely separated by male and female divisions), though it is unknown which floor of The Bathhouse they sleep in. It is accentuated that their living space is extremely cramped and limited compared to Yubaba's office and Boh's room. It is unknown if workers higher on the job ladder have private quarters.
The Boiler Room
Located below ground (but can be accessed by side stairs jutting outside the exterior of The Bathhouse), the Boiler Room is home to Kamajī and countless Sootballs. Most of the room is taken up by an imposing furnace. Its walls are lined with drawers containing herbs that Kamajī memorizes in order to send herbal water up to the baths. The rest of the space is largely empty, save for a large wooden structure that acts as Kamajī's bed and workplace as well as the multiple holes in the wall that act as living space for the Susuwatari. Haku stays here as he recuperates from his magical injuries due to Kamajī's medicinal knowledge.
The ground floor (地 ji, lit. ground) is seemingly dedicated to kitchens and customer-use baths. Due to their popular and constant use, some of the baths are notoriously known to be extremely dirty. During Chihiro's stay as a worker, she is assigned (with Lin) to clean the biggest and dirtiest tub on the ground floor, which, according to Lin, was one that hadn't been cleaned in months.
The second floor (二天 niten, lit. second heaven) is dedicated to traditional Japanese tatami-matted dining rooms for customers. It is first shown during Chihiro's elevator ride through the building complex with the Radish Spirit. A long hallway with rooms separated by rice paper wooden doors line the second floor. They also seem quite popular with customers, as seen when all rooms are occupied Chihiro arrives on the level.
The top floor (天 ten, lit. heaven) has two doors, with the right one having a talking door knocker. The left door is never opened, but the right door is home to Yubaba's office and Boh's room. It is an opulently-built, largely unoccupied space lined with expensive vases accentuated by intricate architecture. Yubaba's office lies on this floor, conjoined with Boh's bedroom. Multiple large wooden doors, which close off at least four other rooms, block the path to Yubaba's office, followed by many, twisting hallways. As shown by Haku, the top floor can also be accessed by a long, spiraling set of stone stairs.