Q: Some years ago the water supply in north Devon was considered the best in Britain. Now it has acquired the taste and smell of a swimming pool. Could anyone recommend a simple and efficient process for removing the noxious chlorine vapours that issue from the tap in the morning, so that I can make a decent cup of tea?
A: If chlorinated water is placed in an open container and left in the refrigerator or even on the kitchen table, it will lose all its chlorine within two hours. Sometimes, the original flavour of the water that the chlorine had masked can once again be tasted.
The reason the chlorine leaves the water is that the partition of chlorine between water and air favours the air once the system is open.
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This is one effect of Henry鈥檚 law. There are two other aspects worthy of mention. First, if your local water authority uses chloramine instead of chlorine there is no unpleasant taste of chlorine but the effectiveness is the same. Secondly, in some parts of the world the taste of chlorine is a good indicator that the water is actually fit for human consumption.