A waterproof fabric is a material that is either inherently, or has been specially treated, to completely block the penetration of liquid water. The core function is to create a total barrier against water. This is often achieved by coating (like Polyurethane - PU or PVC) or laminating (like with a thin membrane such as PTFE/ePTFE, famously Gore-Tex) the base fabric.Water-Resistant fabrics can repel light moisture for a short time (often with a Durable Water Repellent or DWR finish), but will eventually soak through under pressure or prolonged exposure.