How do you waterproof ski pants?

Most ski pants already have a waterproof coating, but you can repair and restore the coating when you wash them. First, run them through a delicate, cold water cycle. Use laundry detergent specially formulated for waterproof outerwear. Add in a wash-in waterproofing solution with the detergent. Make sure your wash-in waterproofing solution is designed for waterproofing clothes. When their done washing, hang the pants up to dry. Once they're fully dry, pray them with a spray-on water repellent that is specially designed for waterproofing clothing. That should help restore their waterproof coating so you can get back out on the slopes!