The design is the visual features of the MAT FOR SINGLE BOWL PET WATER/FOOD STATION shown with solid lines in the drawings, whether those features are features of one of shape, configuration, ornament or pattern or are a combination of any of these features. Broken lines are used to indicate disclaimed portions that do not form part of the design. Drawings of the design are included, as follows: FIG. 1 is a top perspective view of a MAT FOR SINGLE BOWL PET WATER/FOOD STATION, according to our design; FIG. 2 is a top view thereof; FIG. 3 is a front view thereof; FIG. 4 is a rear view thereof; FIG. 5 is a left side view thereof; FIG. 6 is a cross sectional view taken along a line extending side-to-side and midway through FIG. 2; FIG. 7 is a cross sectional view taken along a line extending front-to-back and midway through FIG. 2; FIG. 8 is a top perspective view of a MAT FOR SINGLE BOWL PET WATER/FOOD STATION, according to a first variant of our design; FIG. 9 is a top view thereof; FIG. 10 is a front view thereof; FIG. 11 is a rear view thereof; FIG. 12 is a left side view thereof; FIG. 13 is a cross sectional view taken along a line extending side-to-side and midway through FIG. 9; FIG. 14 is a cross sectional view taken along a line extending front-to-back and midway through FIG. 9; FIG. 15 is a top perspective view of a MAT FOR SINGLE BOWL PET WATER/FOOD STATION, according to a second variant of our design; FIG. 16 is a top view thereof; FIG. 17 is a front view thereof; FIG. 18 is a rear view thereof; FIG. 19 is a left side view thereof; FIG. 20 is a cross sectional view taken along a line extending side-to-side and midway through FIG. 16; FIG. 21 is a cross sectional view taken along a line extending front-to-back and midway through FIG. 16; FIG. 22 is a top perspective view of a MAT FOR SINGLE BOWL PET WATER/FOOD STATION, according to a third variant of our design; FIG. 23 is a top view thereof; FIG. 24 is a front view thereof; FIG. 25 is a rear view thereof; FIG. 26 is a left side view thereof; FIG. 27 is a cross sectional view taken along a line extending side-to-side and midway through FIG. 23; FIG. 28 is a cross sectional view taken along a line extending front-to-back and midway through FIG. 23; FIG. 29 is a top perspective view of a MAT FOR SINGLE BOWL PET WATER/FOOD STATION, according to a fourth variant of our design; FIG. 30 is a top view thereof; FIG. 31 is a front view thereof; FIG. 32 is a rear view thereof; FIG. 33 is a left side view thereof; FIG. 34 is a cross sectional view taken along a line extending side-to-side and midway through FIG. 30; FIG. 35 is a cross sectional view taken along a line extending front-to-back and midway through FIG. 30; FIG. 36 is a top perspective view of a MAT FOR SINGLE BOWL PET WATER/FOOD STATION, according to a fifth variant of our design; FIG. 37 is a top view thereof; FIG. 38 is a front view thereof; FIG. 39 is a rear view thereof; FIG. 40 is a left side view thereof; FIG. 41 is a cross sectional view taken along a line extending side-to-side and midway through FIG. 38; FIG. 42 is a cross sectional view taken along a line extending front-to-back and midway through FIG. 38; FIG. 43 is a top perspective view of a MAT FOR SINGLE BOWL PET WATER/FOOD STATION, according to a sixth variant of our design; FIG. 44 is a top view thereof; FIG. 45 is a front view thereof; FIG. 46 is a rear view thereof; FIG. 47 is a left side view thereof; FIG. 48 is a cross sectional view taken along a line extending side-to-side and midway through FIG. 44; FIG. 49 is a cross sectional view taken along a line extending front-to-back and midway through FIG. 44.