Water Tank

FIG. 1 is a front and right side perspective view of a water tank showing our new design; FIG. 2 is a rear and left side perspective view thereof; FIG. 3 is a front elevational view thereof; FIG. 4 is a rear elevational view thereof; FIG. 5 is a left side elevational view thereof; FIG. 6 is a right side elevational view thereof; FIG. 7 is a top plan view thereof; FIG. 8 is a bottom plan view thereof; and, FIG. 9 is an enlarged view of portion 9 shown in FIG. 8 . The dash-dash broken lines in the drawings depict portions of the water tank that form no part of the claimed design. The dot-dash broken lines in the drawings depict the boundaries of the enlarged views that form no part of the claimed design.