This question comes up very, very often. There is NEVER a valid reason to root ANY plant in water unless it is a water plant, like a water lily!
Break off a stem of your ivy, strip the bottom 2 or 3 leaf joints, bury those in POTTING SOIL, keep moist until the top begins to grow, and you will know it is rooted. Devil's ivy is probably the easiest plant to root that exists. Why would you want to switch to rooting in water? Water roots will NOT work in soil. Even if they did, when you pot the cutting, the delicate water roots break off from the soil being added around the plant.