If you’ve discovered that your rain jacket isn’t as waterproof as it used to be, you can rehabilitate the waterproofing.
Wash and dry to refresh existing coatings
Most rainwear have a Durable Water Repellent (DWR) coating to keep water from fully penetrating your jacket’s exterior. High tech membranes such as GoreTex remain waterproof, but the water repellent in your shell can and does wear out.
I continue to use and recommend the spray-on and wash-in products from NikWax to renew the water repelling properties.
First, wash your rain gear in a cleaner such as Nikwax Tech Wash, which is specifically designed to enhance DWR coatings. Nikwax claims that standard laundry detergents leave hydrophilic (or water attracting) residues in your apparel. The result: Your jacket and rain paints absorb water. Using a product like Tech Wash removes these detergent residues.
Tech Wash is pricey stuff. The MSDS for Tech Wash says it’s made of “potassium soaps and additives,” so I imagine many non-detergent laundry soaps should be fairly safe for your water repellent coating. Your mileage may vary, buyer beware, etc. Some laundry cleaners popular with athletes such as Sports Suds are, in fact, detergents, but some people report good results with the various “sports wash” detergents that claim to be residue free.
After that, some DWR coatings can be ‘refreshed’ by simply tossing it into the dryer. The heat of the dryer reactivates the water repellent property of the fabric. (Note: Read your fabric care instructions – not all materials are the same in this regard.)
Add-in water repellents
If washing and cleaning isn’t enough, Nikwax makes replacement DWR coatings. For the hardshell rain jackets many of us in the Bay Area use, Nikwax says to use TX Direct Wash. You pour TX Direct Wash into the wash with your raingear.
Softshell jackets and other apparel are treated with Nikwax Softshell Proof.
NikWax products are biodegradable, water based and non-toxic unless you ingest large quantities, so don’t do that.
This stuff works.
If you’re skeptical, NikWax North America offers a free Gear Rehab Service. Send in once piece of wearable gear, and NikWax will clean and refresh the waterproofing on it for free. There are limitations and provisos so read the rules, but it’s a rocking deal. NikWax had a free “Gear Rehab Service” to try before you buy for several years, but that program seems to be cancelled for 2015.