Why won't the mallards go in the water?

Mallards prefer still quiet water, but also spend a significant amount of time sitting on the grass, or waddling around pecking at food. If the mallards won't go in the water, look at water temperature, water quality, flow rate, or presence of a predator. Domestic ducks need a large bathtub sized water container for swimming, but will avoid soiled and stagnant water.