
My Puppy started regurgitating mainly water...
Then she processed to throwing up food also.
She was taken to vets and had an infection in her stomach and sphincter which had caused the acid from her stomach to leak in her esophagus (sorry if I have spelled the words incorrectly!).
The vet thinks she has had the infection for a while and our older dog dying caused it to flare up, cause the big symptoms and be found!
The infection has now been treated and she is on a road to recovery but it will take a while for her to completely heal if ever, she might have scarring for the rest of her life.
I would definitely get your puppy checked by vet, maybe get an endoscopy done as he could for example have a lazy esophagus sphincter meaning he might be also suffering from heartburns etc and might need help with that. If all that area is inflamed it could be enough to make him be sick after drinking water...
Our puppy was not really showing anything that would made us to feel she is in pain (I understand heartburn can be pretty painful) but she must have been as endoscopy showed ulcering where the acid had been doing the damage.
Looking back, only thing that was different was that she was drinking little more than usually for few months before it all was found.
Drinking would have made the burning feeling go away.
Reason why I'm mentioning this is that she definitely was not drinking worryingly large amounts taking in consideration it is hot and summertime but more little drinks here and there which for a puppy that loves water (mouthing, playing, anything to do with water)did not make us alarmed...
Obviously we are now feeling guilty of not realising anything was wrong before the infection caused her to get properly ill, get high temperature etc...