Is Reverse Osmosis Water Good (or bad) For Us?
Given that I’m writing a book about water, accepting an offer to review a home water filter made sense. But now it’s on my kitchen counter, I’m not sure if I want to use it. My reservation is this — how pure is too pure?
Reverse osmosis (RO) is typically used to desalinate salt water or seawater into drinking water. For hundreds if not thousands of years, desalination was achieved by heating water and condensing the steam (distillation): great on a small scale, if you’re a sailor using the sun to produce a cup of water, but terribly energy expensive on a large scale.
RO was a game changer when it became commercially available in the mid 20th century. By using an ultrafine membrane to push the water through, it leaves salt and impurities on one side and pure water on the other. Today, over 16,000 desalination plants around the world produce drinking water, the largest being in Saudi Arabia, the United Arab Emirates and Israel.
In human history, however, the water we drink has never been chemically pure H2O. All water contains small amounts of minerals and organic matter, some of which are bad for us — see waterborne disease — but some are crucial for our health.
The World Health Organisation (WHO) recommends that drinking water should contain at a minimum 10 mg/L of Magnesium, 100 mg/L…
