The ornamental design for a watertimer, as shown and described.
FIG. 1 is a perspective view of a water timer showing our new design;
FIG. 2 is a front elevational view showing the design for the water timer of FIG. 1;
FIG. 3 is a right side elevational view showing the design for the water timer of FIG. 1;
FIG. 4 is left side elevational view showing the design for the water timer of FIG. 1;
FIG. 5 is a top plan view showing the design for the water timer of FIG. 1; and,
FIG. 6 is a bottom plan view showing the design for the water timer of FIG. 1.
The broken line showing of portions of the water timer in the drawings is included for illustrative purposes only and forms no part of the claimed design.