Chlorine is the disinfectant most commonly used to keep supplies of drinking water clean and free from bacteria. In developing countries, householders may add their own chlorine after water has been drawn from a source such as a well or pump, whilst in a country like the UK, the chlorine levels of your drinking water will be set by your water provider. Chlorine has been used in this way for over a hundred years, and technology has advanced to the point where water suppliers are able to use the minimum amount necessary to actually get the job of killing bacteria done.
Despite the ubiquity and accepted safety of chlorine, some people are still concerned about possible side effects and links to ill health. After all, this is a substance which the average person is going to ingest many times daily, and so safety is of the utmost importance. Allied to this is the fact that some people are especially sensitive to the presence of chlorine in their water, finding the taste and smell unpleasant. Bearing all of this in mind it’s useful to be able to keep an eye on the levels of chlorine in your own water supply, and doing so is relatively simple.
The most common means of monitoring chlorine levels is known, technically, as the dpd (diethyl paraphenylene diamine) test. This test involves collecting a sample of your water then adding a tablet which colours the water red. The strength of this colour can then be compared to a chart which is supplied as part of the testing kit, with a stronger shade of red indicating a higher residual concentration of chlorine.