You don't have to stop the coffee, maybe just cut down. Water is more important as the coffee doesn't count to your 2 1/4lt - 4 pints a day. Coffee can cause diarrhea and dehydration.
Caffeine content of decaffeinated coffee
Almost all brands of decaffeinated coffee still contain some caffeine. Drinking five to ten cups of decaffeinated coffee could deliver as much caffeine as would one or two cups of regular coffee, according to research at the University of Florida Maples Center for Forensic Medicine. In one independent research on 10 popular decaffeinated coffees, researchers found that all but one contained caffeine. The 16-ounce cups of coffee samples contained caffeine in the range of 8.6 milligrams to 13.9 milligrams. In another similar study of popular brands of decaf coffees, the caffeine content was anywhere from 3 milligrams and up to 32 milligrams. However, in June 2004, a naturally caffeine-free bean was produced.