The ornamental design for a water tap for waterpurifier, as shown and described.
1. Water tap for water purifier
1.1 : Perspective
1.2 : Front
1.3 : Back
1.4 : Left
1.5 : Top
1.6 : Bottom
1.7 : Reference view
1.8 : Reference view 2
The broken lines depict portions of water tap for water purifier that form no part of the claimed design; reproduction 1.1 is a front perspective view of the water tap for water purifier; reproduction 1.2 is a front view thereof; reproduction 1.3 is a back view thereof; reproduction 1.4 is a left view thereof where the right view is a mirror image; reproduction 1.5 is a top view thereof; reproduction 1.6 is a bottom view thereof; reproduction 1.7 is a reference view thereof showing an example of the usage of the subject design in which the claimed design installed at a sink, and forms no part of the claimed design; reproduction 1.8 is a reference view thereof showing the upper and lower water outlet parts are able to rotate 180 degrees and the touch type buttons have been operated, and form no part of the claimed design.