A tub filler and overflow combination device is supported within a common opening formed in a tub wall. Both a flow passage and a drain passage extend through the body of the device to communicate through the common opening in the tub wall. A backflow preventer of the flow passage is slidably removable through the flow outlet for readily servicing the components of the backflow preventer as desired. The flow inlet is parallel and opposite to the flow outlet for ease of manufacturing and for ease of installation into a bathtub.