Will Gore-Tex lose its water-repellency after repeated washings?

A: As regular readers know, a Gore-Tex jacket is more complex than simply a layer of Gore-Tex waterproof-breathable material. Most Gore-Tex in fact consists of three layers: an inner mesh liner (two-ply) or a complete layer of fabric (three-ply); the Gore-Tex or other waterproof membrane material; then the outer "face fabric," which is what you see when the jacket is on. That in turn has what is called a DWR (for durable water repellent) coating. It's the stuff that makes water bead up and run off the jacket. That's important because if the face fabric gets soaked, or "wets out," then water vapor can't get through the Gore-Tex and out. When that happens, people think the jacket is leaking. After all, the surface material is soaked, and you're wet inside from sweat—it might as well be leaking. So it's important to maintain that DWR layer. Keeping the jacket clean is one way—dirt attracts moisture and grinds away the coating. So an occasional wash is fine, followed by machine drying on moderate heat. That heat actually softens the DWR and spreads it around some, aiding its effectiveness. But there's a tradeoff, because in time washing will also remove the DWR (on balance, though, better to wash than not wash).

Nikwax TX-Direct

So as the DWR wears off or washes off, water no longer beads up. This is where your old Serac jacket finds itself. But it's very possible to rejuvenate the jacket, more or less. I've used, and like, Nikwax TX-Direct Spray-On ($12.50 for the ten-ounce bottle, enough for three or four jackets). You wash the garment, then spray with the Nikwax when it's wet. That'll keep water beading up through several more cycles of use and re-washing. Nikwax also makes a wash-in product that does the same thing, but that can inhibit the ability of the liner to wick moisture, so I'm less inclined to recommend it. Gore makes a similar product called ReviveX ($10 for five ounces), which the Gore folks claim lasts longer than Nikwax. I can't say, because I haven't tried them side by side.