Gore shell fabrics, the outermost fabric layer of a GORE-TEX garment, are treated with an ultra thin polymer coating known as DWR, or durable water repellent. This coating causes water to bead up and roll off the outer layer of fabric, instead of being absorbed. Water repellent outer fabric provides additional insulation and prevents liquid from saturating your garment's outer fabric, a condition known as "wet out" that can make you feel damp and clammy. Your garment may even feel like it's leaking, although it's not. Regular wear and tear, plus exposure to dirt, detergents, and other impurities, causes DWR failure. The effective life of the DWR depends upon how you care for your garment and how rigorously it is used. The most effective way to maintain your garment's water and stain repellency is to wash, rinse, and put it in your dryer. Keep it clean! Be sure to read the care tag in your garment for specific instructions.