Check out this water bottle - one side for your drink and the other for your dog's water. Comes with collapsible travel cup for your dog too http://www.dfordog.co.uk/h-duo-dog-water-bottle-travel-cup.html
Bedlington Terrier - Tip 3 - Hydrate Hydrate Hydrate - Dogs can get dehydrated in hot weather, just like people. Fill your dog’s water bowl with cool water a few times a day. Keep a travel water bowl and jug of water in your trunk to give your dog drinks when you’re away from home.