Shanghai isn’t one of those cities where you can turn on the tap and enjoy a glass of water. Chances are you’d end up with problems–from diarrhea to much worse (the city’s water contains an array of pollutants linked to cancer, says the Beijing Tianjin Water Resources Management Project). Just how bad is Shanghai’s water, and what can you do to limit the risks?

Although the city announced on November 9 that, starting next year, 70 percent of Shanghai’s water will be drawn from the cleaner Qingcaosha Reservoir, most of the current water supply comes from the Huangpu River, which runs 112 kilometers from Tai Lake into the Yangtze. Surface water quality is measured by the Shanghai Classification Standards for Surface Water Environmental Quality, in which clean water is classed as one, two or three, while polluted water is four through six. Only the water in the Yangtze basin reaches level one, meaning that most of Shanghai’s water is of low quality. The worst, level six, is found where Suzhou Creek meets the Huangpu.

There is plenty you can do to minimize contact with polluted water, though, and you’re probably already doing it. Dr. Joseph Chang, Emergency Department Chairman at Shanghai United Family Hospital says, “Make sure that the only water you drink is bottled and sealed, and never put ice in drinks unless you’ve made it yourself using bottled water.” Dr. Chang also advises swimming only in chlorinated pools, never the river or creeks.

Many people believe that simply boiling Shanghai’s water will make it safe to drink, but while boiling kills bacteria and parasites, it doesn’t get rid of pollutants. With evidence of harmful toxins, heavy metals and carcinogens in the water supply, it’s better to always use bottled water when cooking.

Dr. Chang uses tap water to brush his teeth to no adverse effect and says not to panic if you ingest some. “A small amount shouldn’t cause harm. However, you should seek medical help if you are showing any signs of dehydration, vomiting, frequent diarrhea (more than five times a day) or have blood or mucus in your stool.” You should also see a doctor if you start to feel weak or dizzy, get extremely thirsty or have a fever over 101ºF (38.3ºC) for more than three days.

While we might not be living in a city with water that’s clean enough to drink, simple measures can ensure our health isn’t compromised.

Does the water quality in Shanghai concern you? What steps are you taking to make sure you're staying healthy?

Want to read more Health Matters articles? See this article about air pollution in Shanghai.