Potential causes for increased salivation (making them more thirsty and possible regurg):
Know that whatever you give your dog needs to be evaluated carefully for many reasons. From hydration standpoint, make sure you aren’t making them even more thirsty by using substances that can increase that need. Liquids that are higher sodium  content are not good. Keep sodium as low or no as possible. When a dog gets thirsty it can drool which might also increase salivation which can in turn cause regurgitation.
–   READ all contents of what is put in your dogs mouth.
–   KNOW that if you are cooking your dogs food, you may be adding higher amounts of sodium thru natural foods so research each item well

Ideas for keeping your ME dog hydrated:
Thick It with no sugar – pharmacy, Walmart
Lickit Stik (like a thick broth in a roll on bottle) – Petsmart, Petco
Smart water (has electrolytes and no sodium) – grocery
Mixed in with food (blended in the blender works best for most)
Knox Blocks made with broth (use low sodium broth) – see Knox Blox recipes
Plain ice cubes with pumpkin (pure pumpkin, NOT pie filling) in them
Thickened coconut milk
Frosty Paws – freezer department of your grocery
Plain Ensure type liquid in vanilla flavor and can dilute with water as well
Chicken broth Jello (use low or no sodium broth)
Add liberal amounts of water if using dry food
Add water to your blended food to make a slurry
Making Gelatin Cubes (water mixed with gelatin then frozen)
Ice cubes
Adding “Thick-It” to the water (Can find this in your local drug store. It’s is often times used with stroke victims that have trouble swallowing.)
Some dogs do okay with plain water if they are in their chairs in an upright position

 IMPORTANT: Be very careful because some ingredients are not good for dogs (the main ingredient in the thickening agents seems to be cornstarch, so perhaps corn-sensitive dogs would no tolerate it).

Even our ME dogs are at risk for kidney stones:
–   Ensure multiple times a day your method of providing fresh water is available daily.
–   Add small amounts of flavoring (e.g. salt-free bouillon) to make water more palatable if/as needed (low or no sodium so it doesn’t make your dog more thirsty)
–   Offer ice cubes as treats if your dog can handle them. DO NOT give them when your dog has been playing outside in the heat. Wait until your dog cools down.
–   Use canned dog food to help prevent concentrated urine if you are able to mix with your consistency for feeding.