on my motorcycle and fishing gear, I use nikwax products, they make a detergent just for goretex like materials, then a wash-in treatment to bring the waterproofness and breathability back. stuff is like new after using it. you can order it at tons of places on-line, I think amazon had best price last time I bought some.
http://www.nikwax.com/en-us/
Revivex or nikwax...always wash yer waterproof garments first use the special wash treatment first ..then either Nik Wax or Revivex, also some companies will prefer you use Scotch Guard like my Pacific Fly Group jacket thats served me since 96' an it has been through the grinder .