How long has this been going on? Is it after he drinks? Does he drink quickly?
Is the dog eating and drinking normally? (the same ammount)
Is there any vomiting of stomach contents or is there any diarrhea?
Thank you for that information. Dogs can get an acid reflux which would produce a spit up of stomach fluids. Causes can be attributed to a hiatal hernia, or poor positioning when eating or drinking. Try putting a less amount of water in the dish so she can't get a lot of water at once. Placing several water dishes around the house with limited water may also help. Raise the water and food dishes to chin height so there is not bending to the floor. You can also give some Pepcid AC to help with this.
Pepcid info and dosing; http://www.petplace.com/drug-library/famotidine-pepcid/page1.aspx
If the dog is still eating and drinking, shows no vomiting, diarrhea , or fever then it would not be a big concern. If any off the above symptoms appear then she should be checked .
If it seems as if she is choking then I would have her seen as there may be a problem with the trachea. If the choking episodes seem to last for one to two minutes and like the dog is sucking air in through the nose , choking or gagging, then subside, you may actually be seeing a reverse sneeze which is common in dogs. When this happens again rub under the neck and see if it subsides a bit quicker. If it does then you are probably looking at a reverse sneeze.