How much water is too much?

A sudden increase in water consumption can signal the onset of diabetes, kidney problems, or an acute toxicity and should be evaluated by a vet. By itself, drinking a lot of water is not necessarily dangerous (though like anything, too much water can be toxic - it depletes the body of necessary salts causing hyponatremia), though if a dog is drinking to the point of regurgitating they should probably be encouraged to pace themselves if only to save you a mess.

I've had a couple guests I've had to put on water restrictions for some/all of their visits. Some dogs seem to drink compulsively when stressed, and in those cases offering smaller amounts of water frequently during the day can help keep their drinking under control and their potty breaks predictable.

There is really no limit for water and it all depends on how much the dog wants to drink. However you might want to take your dog to the vet just to make sure your dog is not dehydrated or something is not functioning correctly in their body.

Sometimes there is a lot more splashing than water actually being consumed. We have a water bottle with a ball at the tip and the dog licks the ball and releases the water. This seems to give the dog more water than lapping the dish. (It also helps keep the dogs muzzle from getting all soggy and gooky.) You might want to try a water bottle with this dog. See if it helps. The other nice thing is that you can fill up the bottle and not have to worry about the dog running out of water in their bowl during the day.