Hot water dries out your skin. Taking a shower is always a healthier choice for your skin, but if you have to have a bath, make sure the water is not too hot.

Add a cupful of powdered milk to the bath water. Milk contains lactic acid which will assist your skin in shedding the dead, dry layers and milk protein will help your skin in retaining the moisture.
Moisturize your legs with a rich body lotion right after toweling off. When you apply lotion while your skin is still damp, it locks the moisture in. If you suffer from a very dry skin, it is a good idea to slap that lotion on, at least twice a day.