Bathroom towels should hang low enough to be within easy reach, but not so low that they will drag on the ground. Consider the people using the bathroom to determine whether you should adjust above or below the standard height.
The typical bathroom towel rack hangs 48 inches above the floor. This is mid-chest height for most adults. Even with relatively large bath towels that are 60 inches long, the towel will still fall 18 inches above the ground.
In a bathroom specifically for children, the towel rack usually is only 36 inches above the ground. This allows a child to hang his towel up without climbing onto a stool. Prevent towels from dragging by purchasing towels that are no more than 52 inches long, which leaves 10 inches between the towel and the floor.
Hang the towel rack slightly higher or lower than normal if your bathroom decor necessitates it. For example, if you have a tile border going around your bathroom 48 inches above the floor, hang the towel rack just above or below that so you do not have to affix it to the tile.