Moisturize Your Nails

Your nails contain no fat, so they can't naturally hold in moisture. Instead, try soaking them in tepid water, then applying a moisturizer, which will help lock in the water.
You may also want to try products that contain phospholipids, urea, or lactic acid all are "humectants." Complex 15, Aquaderm, and Moisturel are worth trying, or you may want to use an old standby petroleum jelly. Don't forget to reapply moisturizer after wetting or washing your hands or bathing.
But don't overdo it nails become soft and brittle when exposed to too much hand lotion and other moisturizers. Nails may be extremely soft right after a lot of time underwater or may become dried out from repeated soaking and drying.
If your nail becomes infected, particularly with a yeast organism, it's important to avoid prolonged exposure to water and to keep the nail area as dry as possible, since infecting organisms generally prefer warm, moist environments.