The ornamental design for a waterfilter, as shown and described.
FIG. 1 is a perspective view according to the present invention;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a left view thereof;
FIG. 5 is a right view thereof;
FIG. 6 is a top view thereof; and,
FIG. 7 is a bottom view of a water filter thereof.
The broken lines in FIGS. 1 and 3-5 depict portions of the water filter that form no part of the claimed design. In FIGS. 6 and 7, the broken lines and areas within and adjacent to solid lines depict portions of the water filter that form no part of the claimed design. The dot dash dot broken line in FIG. 7 denotes a boundary to the claim and forms no part thereof.