The bath tub (10) having side access has a main tub body (12), a door support, a tambour door assembly (16), a door seal 18 and a control system (20). The door support includes door guide assemblies (64). A tambour door (66) with a plurality of tambour slats (76 or 401) and a flexible impervious membrane (86) is guided by the door guide assemblies (64). The tambour door (66) is in a horizontal position under the floor (27) when it is open and in a vertical position closing the open side (28) of the main tub body (12) when it is closed. A seal (18) seals between the main tub body and the membrane (86). The seal (18) includes a tube (155) that is inflated to seal between the main tub (12) and the tambour door (66). The control system (20) closes the drain 46 when the tambour door (66) is closed and the seal (18) is inflated and the tambour door (66) is constrained in the closed position. The tambour door is constrained in the closed position until the control system 48 senses that the water level in the tub has dropped below a predetermined level and the seal (18) is deflated. A valance (114) limits movement of the tambour door (66) away from the seal (18).