Friday, January 08, 2010

Is it safe to drink Beijing tap water?

The water in our Beijing apartment looks, smells, and (yes I risked it) tastes just fine. But is it safe to drink?  Nearly everyone I know -- foreigners as well as locals -- refuse to drink water straight out of the tap, and some of the more paranoid types use bottled water for virtually everything except bathing. It’s pretty common among ex-pat households to keep a bottle of mineral water in the bathroom for brushing teeth.  Even though the water appears to be just fine, “you can’t be too careful”, they say, and you never know what the city government lets into that water, or the pipes that carry it to my tap:  lead?  pesticides? heavy metals?  We know one family that makes their Ayi (housekeeper) painstakingly wash and dry every leaf of lettuce before eating it.

I’m not that paranoid, but I am curious, so on my last trip to Japan I bought a water testing kit from Kyoritsu Labs, a small company that sells low-cost test packs for people like me.

Well water test kit from

The kit, which I bought in Tokyo at Tokyu Hands for 1,365 yen (less than $20), comes with 5 test tubes, each containing a small amount of reagent. You pop a pin on the tube, insert a small amount of the water to be tested, and after a few minutes compare the color of the mixture to a color chart in the instruction manual.

They give you two copies of the pH test tube, so for practice I tried it on a sample of distilled water:

pH test for iron (Fe).

The result looks pretty close to the 7.0 that means neutral pH, what you would expect.  Looks like the test works, at least on this.

Next I ran the same test on the tap water:

pH test for Beijing tap water.

A pH level of 8.0 means the water is fairly alkaline.  Since the human body keeps blood at a range of 7.35 to 7.45, some people (including the Singularity champion who I respect, Ray Kurzweil) think drinking alkaline water is healthy.  In fact, some health nuts buy expensive machines ($1000+) so they can drink it all the time.  Anyway, the point here is that probably the pH levels in my tap water aren’t bad.

Next, I tested iron (Fe) and found nothing, which is good.

pH test for iron (Fe).

What about water hardness?


The water is slightly hard: between 100 and 200 total calcium plus magnesium. This is obvious from taking a shower: it feels like the shampoo won’t come out of your hair, and it’s not easy to get a good lather going with a bar of soap.  But, at least according to the World Health Organization, this doesn’t seem to have an effect on health.

Another test, for Chemical Oxygen Demand, doesn’t check for any chemicals per se, but just the level at which oxygen is absorbed in the water, considered a proxy for the amount of organic compounds (i.e. living things).  The closer you can get to zero the better, but our level is under 5 and considered fine.  To give you some perspective, Switzerland apparently has a law prohibiting the dumping of water that is over 200.  As you can see, that’s not us:


The final test measures nitrite ion concentration, which is associated with sewage and/or fertilizer.  Ideally, this would be zero, but ours tests at just under 0.5 parts per million (ppm).  The US Environmental Protection Agency sets the limit at 1 ppm, so we are okay, though of course I wish the number were lower.Nitrite-Ion = 0.2. Well water test kit from

This kit is intended for testing well water, which is the closest I could find to what I wanted, so these are the only tests included.  I’ve asked around and can’t find a test kit for lead or other heavy metals that seem to bother people the most, at least for long-term exposure.  If you know of any low-cost, portable tests for this, please tell me in the comments.

The bottom line is that I wasn’t able to find anything that proves we shouldn’t drink the tap water.  This means nothing, because of course those who are paranoid careful will fear something I wasn’t able to test. On the other hand, I didn’t test the bottled water at all, so it’s not like you’re really safe that way either. As always moderation and common sense seem to be the best policy, but I’m reassured that at least on a few basic measures, the tap water here is not obviously dangerous.