Here is a useful table by the Kentucky Cooperative Extension with the water content of common fruits and vegetables. Fruits and vegetables have the highest water content compared to most foods. Romaine lettuce, tomatoes, watercress, zucchini, asparagus, cantaloupe, grapefruit, and honeydew melon are among the highest percentage of water. Meeting your recommended water intake each day is very important for many reasons. This is just another reason why fruits and vegetables are extremely beneficial!