I’m a bit maxed out on my air pollution blogging and now am focused more on other environmental issues, such as water safety. A couple months ago I invited the PureLiving China indoor environmental testing company to our home for an inspection, and I blogged about their findings last month. I still had a lot of questions about water, so company founder Louie Cheng and I have been corresponding by email. Our discussion is very topical for most in China, so here’s our conversation below:

Q. Your company, PureLiving China, has sampled many water sources both here in Beijing as well as Shanghai. What are the most common problems you see in the tap water?

The situation is different in Beijing and Shanghai. Beijing tends to have bacterial problems a little more often. I would attribute this to older piping infrastructure and also because Shanghai has been getting more of its water from the Qingcaosha Reservoir, which has much higher quality than the majority of Chinese groundwater. Shanghai has higher chlorine in some districts. Shanghai also has some high levels of copper. Both often have either high chlorine (used as a disinfectant) or sometimes low chlorine (if far from the municipal treatment plant). However, a key thing to note is that BJ & SH are split into multiple districts — 6 in SH alone — and each district has its own treatment company. So, methods, as well as water quality vary significantly based on location.

Q. What about shower water samples — what common problems do you find?

Shower water is very much the same as the tap, since the only difference is maybe 10-30 meters of plumbing.

Q. Many expats use delivered water in those large 19 liter jugs. Have you tested those, and what are your concerns, if any?

Yes, generally we don’t find many problems. During hot weather, we have found elevated bacteria. The main issue is that the same water is found in multiple brands, which wouldn’t normally happen if they were “legit”. My guess is that a distributor is filling different brands with the same filtered water. It’s a problem if you order distilled because of dietary requirements or say dialysis, and you got spring water. The safest thing is to buy where the distribution is owned by the bottler. The second preventative is to make sure you disinfect your water dispenser every 6-8 weeks. Simple instructions in English and Chinese are posted on our website blog here.

Q. There are many types of water filters, from tabletop to under the sink, from simple filters to reverse osmosis. What’s your general findings on these?

Effectiveness depends on the level of contamination of source water. Many times, any of them are fine if you don’t have problems. However, in general, from least protection to most is something like this: ceramic jugs (Berkee), boiling, whole house filters, Brita, multistage carbon, distillation, reverse osmosis.

Q. Many people think Beijing’s water is too hard; what’s your best advice to help with this?

Use a water softener (assuming you don’t have a sodium intake problem). Some shower filters with KDF/carbon mix also do help.

Q. Parents of newborns are always worried about having clean water for infant formula, and always want to know what’s the safest way in Beijing to get this. Many use Watson’s distilled; some boil; some use filters; some use imported bottled water. What’s your opinion on the safest approach?

I covered this above, but either get a reverse osmosis system certified by NSF for not only contaminant reduction performance, but also manufacturing quality (ie. no parts leaching lead). Or, get bottled water by someone who delivers their own water.

Q. Calcium levels in the tap water always leave a whitish residue on pans, tea kettles, faucets and humidifiers. What’s the best way to fix this?

My research suggested only reverse osmosis filters could help, what’s your opinion? Scale is caused by calcium carbonate and magnesium — reverse osmosis definitely helps. I know that shower filters do help remove as well, and anything that does ion exchange, such as softeners.

Q. Anything else you’d like to mention?

One additional tidbit you could add is that we very frequently find that water from water filters is worse than tap. Why? If the filter has not been changed and it gets too full, it can start leaching the contaminants back into the effluent. Also, if you go on vacation and don’t have a filter with silver or other antimicrobial, you can get some bacteria that grows in the filter. So, have someone turn on your kitchen filter for a few minutes every month or so.