Everything we wash down the plughole, as well as what seeps through the ground or falls from the sky, ends up in our water supply. This includes human waste, detergents and even hormones from women on the Pill. Other contaminants include pesticides, lead, nitrate and iron. The Drinking Water Inspectorate (DWI) is a government-regulated body that monitors and tests the UK's water. Companies must meet stringent safety criteria. However, water still contains some minerals and chemicals that could pose a threat to our health. Studies have shown that chlorine, used to disinfect water and remove bacteria, has been linked to an increased risk of rectal and bladder cancers. The government has issued warnings about this, and research has shown a link between aluminium in water and Alzheimer's. All tap water is heavily treated, going through several processes to make it suitable for human consumption. By 2003, the DWI announced that 99.87 per cent of all tap water tested met its standards.

YOU CAN'T IMPROVE YOUR TAP WATER??

Tap water

Filter it

Fruit-flavoured water

Bottled water; which is better?

Tap water varies in taste and mineral content, depending on where it comes from. According to the DWI, two thirds of British drinking water comes from surface water, including reservoirs, lakes and rivers. The rest comes from rainwater which seeps through porous rocks, then is drilled out. Some areas have hard water, which is full of magnesium and calcium compounds, while others have soft water, which is free of these. Tap water can contain traces of a range of minerals from aluminium to iron, which means the taste varies from region to region in this country. If you're sensitive to the taste of your H2O or would like to filter it, you can invest in a jug filter (around £15). Or you water filter tap on the side of your kitchen sink. Expect an initial outlay of around £500-£700, with cartridges setting you back £100 a year.