While CORDURA® and Ballistic Nylon has a waterproof poly-urethane backing, our gear is classified as water-resistant. Waterproof bags require heat sealed and taped seams; ours are sewn. Every stitch can be considered a “hole” for water to leak through. CORDURA® Nylon and Ballistic Nylon can be treated with an additional ScotchGuard Heavy Duty Water Shield Spray if necessary. Watch the demonstration video there or follow manufacturer’s water-treatment product instructions on the label for best results.