This is a three-step process—wash, treat, and dry. If you let your rain gear air-dry, the process will take about 24 hours. If you opt to dry your clothes on low or no-heat tumble dry, it can take a few hours, by putting your gear through two cycles in the washing machine and one cycle in the dryer.
If there are obvious stains on your jacket, spot treat them with a dab of tech wash. Let it sit for a few minutes, and then buff or rub the stains to loosen them.
When you’re using the tech wash or other rain-gear-specific product, put no more than two items of rain gear in the washing machine at a time, and then add the recommended amount of cleaner to the detergent dispenser. (Nikwax specifies 3 ounces per load.)
Ketric Cooley-Rieders, a wash technician at Truckee Laundry (which specializes in cleaning and waterproofing ski clothing), said you should “wait three minutes before dropping the tech wash in,” because you want the product to disperse throughout the water in the machine to evenly coat everything. Then set the wash cycle to “normal” so that it spins out as much water as possible.
You don’t even have to take your gear out of the washing machine. Just drop the waterproofing formula into the detergent dispenser. Nikwax recommends about 5 ounces of waterproofing formula per two-piece load, depending on how much fabric you will be treating.
You can “drop the waterproofing in right away,” said Cooley-Rieders, instead of waiting like you did for the first wash cycle. But this time, wash the item on a delicate cycle. “A ‘normal’ wash adds an extra spin at the end of the cycle, so it washes out all the waterproofing.” The delicate cycle does not have an extra spin cycle at the end.
If there’s a fleece or fabric liner in your coat or pants, take the item out of the washing machine and hang it up. While your gear is still wet, spray on the waterproofing, holding the bottle about 10 inches away from the clothing to get an even coat. Pay special attention to the back of the shoulders and the cuffs, where the waterproofing most easily rubs off.
Step back and take a look, and if you see any dry spots, go back and spray them again.
Dry your rain gear according to the instructions on the care label. If you decide to air-dry your gear, it will likely take about 24 hours.