The tea houses I went to had a water cooler by the serving table and they get the water in front of you. They prepare the tea and drink with you. I assumed the water was either spring water or filtered. The tea I tasted didn't give me any problems nor had signs of contamination. Afterall, they're trying to sell their product and water quality is the #1 factor to a good cup of tea (not the leaves). I wouldn't take a chance if I didn't see a water cooler or the place was suspicious though. Just make sure the person who serves you drink first :)

The fact, that the staff drinks the tea with you does not mean anything. They can be adopted to microbes in the water.
When we visit Egypt or other african countries, we cannot drink the same water as locals do, because we will get dysenteria.

I suffered no ill effects during my travels in Singapore, Malaysia, Taiwan, and PRC. The hotels supplied bottled water in the rooms, and I brushed my teeth with it. The restaurants supplied bottled water. I found bottled water in convenience stores near all of the hotels. I carried bottled water on walks and tours. I drank tea in dozens of tea shops. I can only hope that your experience mirrors mine. But tell your doctor of your plans, and travel with medicine to ameliorate the effects.

I enjoy coffee as well as tea, and the coffee I encountered in Asia was delicious. I found that folks in PRC are really into soup. So--I had plenty of fluids and I did not get sick from consuming water. Good luck--but I do not think you'll need luck if you take simple precautions.

I do not drink alcohol, but if you do, remember that alcohol can kill many little things that live in water.

My biggest physical complaint was jet lag, caused not so much by the experience of riding in a jet for twenty hours but by living in a reversed temporal universe. I had not realized it would hit me in such a profoundly debilitating fashion. I was there for two weeks before I assumed anything close to human shape. And when I returned to my U.S. home, I had to face the battle again. My advice--if at all possible (i.e., if your job allows it), spend two weeks prior to your departure living in the zone you're going to visit. Mental clarity is a sufficient challenge when I'm in top form; in the fog of jet lag I was a zombie. Snap lots of photos the first few days so you'll have some record of where were you and what you did. :-) Generally, I oppose drugs if they are not prescribed to fight disease, but next time I go, I'll plead and beg and whine to get some sleeping pills to have with me. Perhaps my problem in this particular regard is idiosyncratic. Maybe I'm more sensitive to time zone changes. I live on the west coast, and I encounter the problem (to a lesser extent) when I travel to NYC or Hawaii.

If Asia is on the other side of the globe from where you reside, you might want to carry two watches, one of them kept set to home-time. Phoning home from Asian hotels was incredibly inexpensive. But I'm innumerate, and when I was jet-lagged, working through the math was quite beyond my limited capabilities. Despite my best efforts, I called family members in the middle of their nights.

Do not worry too much. You'll have a great time. Except for the employees of Taipei's flagship TenRen, every person I encountered was kind and friendly.

Best to you,
~geraldo

Water isn't a big issue in China -- bottled water can be had everywhere, and if you're sensitive or worried, just stick to the big name brands (I'd recommend Nestle). There really isn't a place you will go where they won't have bottled water (imagine the waste bottles...).

Water for tea is always boiled, so no worries there either, and NOBODY I've seen will ever serve you tap water.

I brushed my teeth using tap water, and was fine. In fact, I was there for a whole year and never had a major case of stomach issues. I was in the big cities, for the most part, but I think generally you'll be fine.

Now, food... is something else to worry about, and MSG, but that's not tea related :)

Don't drink cold water, but when people are making tea they'll boil the water (and you'll generally see them do it), so it should be fine... folks there generally bring the water to a full boil in my experience. Most of the trains and stuff have water that's been boiled.

Shanghai, at least, has horrible tap water, so most of the tea merchants there use filtered water anyway... it's in their interest to have water that tastes good.

Water for tea is boiled first. That helps. Plus, in my many trips to china i have not had ill effects. I only drank tea or beer out. I did buy bottled water, good brands from 7/11 normally. I did drink some of the local good brands also.