What material will not let water through?

Why Nylon and Polyester Keep You Dry

When it comes to staying dry in wet weather, not all fabrics are created equal. Two of the most reliable materials for blocking water are nylon and polyester. These synthetic fabrics are engineered with a tight weave that naturally resists water absorption, making them go-to choices for outdoor gear and rainwear.

While both fabrics offer water resistance, polyester takes it a step further—especially when treated. A special coating or finish can turn polyester into a fully waterproof barrier, capable of withstanding heavy downpours. That’s why you’ll often find it used in outdoor umbrellas, patio furniture covers, and high-performance raincoats. Its durability and low maintenance make it ideal for items exposed to the elements.

Nylon, on the other hand, is naturally strong and lightweight, with a smooth texture that sheds water reasonably well. However, it usually needs a coating—like polyurethane or silicone—to become truly waterproof. Without treatment, it may eventually absorb moisture over time, especially under prolonged exposure.

One thing to keep in mind is breathability. While both fabrics excel at keeping water out, they don’t always let moisture vapor escape, which can lead to condensation on the inside. That’s why manufacturers often use layered or coated versions to balance waterproofing with comfort.

Ultimately, if you're looking for a fabric that won’t let water through, treated polyester stands out as one of the most effective and widely used options. Whether shielding your backyard furniture or keeping you dry on a rainy hike, these materials prove that smart fabric engineering makes all the difference when the skies open up.