Bath Filler Taps This type of tap sits in the two holes in your bath and is linked together creating a bath filler. Hot and cold water are mixed using the valves on either side and the mixed water runs out of the spout and fills the bath. There are many variations and designs both traditional and modern. The basic bath filler as described above is the most commonly used one. There are more. Such as a three tap hole bath filler. similar in design to the three tap hole basin mixer two valves control the flow to a central bath spout. Other styles are available which fill the bath from the overflow hole and double up as the overflow as well. these type of fillers can be controlled by a pair of valves on the bath or a wall mounted shower valve which also capable of serving a shower head as well.