Nikwax or Grangers for Goretex/Event/Paramo etc same as previous replies. Just an insight-most people wait to long to reproof hard shells, wash regularly every 10 or so times you wear the jacket-don't wait for the jacket to wet out, and don't worry about the machine process wearing out the jacket. As soon as the jacket stops beading, give it one with the Nikwax/Grangers, or administer a pray on the high wear areas (shoulders where the DWR is rubbed off), you'll keep the jacket functional for longer. However-most shells are at best weather/water resistant, even if they state a H/H of 30,000 plus (Hydrostatic Head, anything over 10,000 is considered waterproof-ideally 20-30,000 is good).
Cheers DT