What can you give a dog that won't drink water

A visit to the vet.

I agree Sariss, had to spread the rep.

If you can't get to the vet right away then try pedialyte. This will keep your dog hydrated until you get in to see the vet.

Make some low sodium broth. I have used Gatorade. But Pedialyte works the best like our resident canine whisperer Alty says.

How long has this been going on? Does the dog eat? Is it lethargic?

Are you planning to take it to the Vet?

You can also make ice cubes with Pedialyte or the low sodium broth. My dogs can't resist ice. :)

Have you tried running water?
I know of a few dogs that are reluctant to drink from a bowl but love running water, you can even buy special dog bowls that keep the water moving.

And of coarse the above suggestions are also great, pedialyte for rehydration, ice cubes to encourage him to even get a small amount, adding flavour can work too.

All this is only until you can get him to a vet though ;)