For me it wasn't when or how much but what. At it's worst I was taking prescription medicine ate what I thought was healthy food (whole grain bread, oat cereal) and still had heartburn every night. I am not celiac but eliminating beer, whole grain wheat, and oats got rid of my acid reflux. Wheat, especially the modern variety, is not well tolerated by humans http://news.discovery.com/human/why-you-should-probably-stop.... If you can't give up bread eat Sourdough http://cookusinterruptus.com/blog/?p=4245
This. I live in a major city and our water is majorly chlorinated. I read a bit about this online and thought, sure, what the heck, I'll try eliminating chlorinated water and see what happens.
Now I have an under-counter water filter and all our drinking water has a significant amount of the chlorine filtered out. It made a huge difference for me. YMMV, and of course doesn't mean much for well water.