Both nylon and polyester resist water, but polyester resists it better than nylon. Additionally, polyester's water-resistant properties increase as the thread count rises. However, neither material is fully waterproof unless it's coated with special materials.
Is nylon 100% water resistant?
The question, Is nylon waterproof? is a common one and the short answer is no, nylon is not waterproof. As a fabric, it will actually absorb water and when wet, will allow water to pass through it.
Is nylon waterproof and breathable?
Waterproof breathable fabrics consist of an outer layer called the “face fabric”, usually made of nylon or polyester, and a laminated membrane or coating, usually made of ePTFE (expanded Polytetrafluoroethylene, also known as Teflon®) or PU (Polyurethane).