Your water supply – how is it treated?

In many countries water is purified by government owned or run organizations or by large corporations. Although some water treatment programs are quite transparent and can be visited in person by any member of the community, others may lie in remote regions or have heightened levels of security, thus preventing the entry of members of the public. It’s important to your own health and peace of mind that you understand just how the water you drink is treated, however. In the UK there are a number of companies that treat the water supply available to the public, and these companies are monitored and tested regularly by the Drinking Water Inspectorate. The Department of Environment, Food and Rural Affairs (DEFRA) also pays close attention to the general water supply and regularly publishes reports.

In general, your water supply is treated in a way that meets the demands of the various water monitoring boards both within the UK and the EU. After the initial pumping or collecting of the water (depending on the water source, your water may come from an underground supply, a reservoir, or perhaps even a flowing body of water), it is then screened (all large objects are removed, such as branches and debris); stored in a reservoir or large tank; pre-conditioned with soda-ash to reduce hardness; and chlorinated as the water flows in to the treatment facility to prevent early growth of organisms prior to treatment. Once within the facility the water is flocculated, or clarified. This means that the water treated to remove any unnecessary turbidity and colour. After flowing through sedimentation tanks to remove any excess floc, the water is then filtered through a rapid sand filter. Disinfection then takes place in an effort to remove any final nasty contaminants including bacteria and viruses. If necessary the water may be treated further (fluoridation is an example of additional treatment).