Abstract: A bathtub has a doorway in a sidewall thereof. A door is slidably mounted to guides on guide followers mounted to both the door and the guides. The guide followers carry the door along a substantially horizontal translation along the sidewall between open and closed positions. A releasable latch and cooperating latch actuator is mounted to the door for releasable latching engagement of the door when in a watertight sealed engagement in the doorway, and for releasing the door from such engagement upon actuation by a user of the latch actuator into its release position. A passive hydrostatic seal is mounted so as to be sandwiched between the door and the doorway doorframe when the door is closed.