Written on here a few times about this.... Be aware there are some real nasties lurking around in China, especially in the water. As you say, it's not just the water you drink, it's the water you wash your veg with, brushing your teeth, mixing things with, ice cubes to name but a few.
Number 1 .... don't rely on electric kettles to boil tap water or water from unknown source for coffee and other drinks, many are fooled into thinking that once boiled it's OK...''It's Not'' water has to boil for at least 3 minutes to become safe to drink, and kettles don't boil for 3 minutes, they switch off when boiled!!! So always use bottled water for making coffee, washing veg, making ice cubes and brushing your teeth...
Number 2 .... Try to avoid food street vendors or at the very least, those that in anyway look suspect. This also includes rough looking restaurants too. Any fresh fruit drink street vendors, ice cream vendors....
You may not know this but the biggest loss of working man hours in China is due to water bourne bugs, and infected foods.... So ALWAYS use a little commonsense when your out and about, because if you don't, these bugs will knock you down flat, and you'll stay that way for at least 3 to 4 days with medication, without medication you can get in serious trouble... it just ain't worth it !!!
Oiler,
No, your wrong your body doesn't get used to it at all ...re-infect yourself and you WILL go down again, and just as bad as the first time!!!!
David...