Your tap water
In addition to H2O your water contains a number of substances. Most of these are perfectly harmless and that water would taste foul if they weren't there (try tasting distilled water if you're not convinced!). Others are safe in the minute concentrations found in tap water.
The substances we have to check for include:
CALCIUM - occurs naturally especially where the water flows through limestone or chalk.
SULPHATE, MAGNESIUM, SODIUM AND POTASSIUM - naturally occurring as a result of the passage of water through minerals.
MANGANESE - occurs naturally and is an essential part of our diet; may also come from the corrosion of cast iron water mains.
IRON - occurs naturally and is removed at the treatment works; may also come from the corrosion of cast iron water mains causing a rusty brown colouration to the water.
ALUMINIUM - found naturally in all water sources; chemical aluminium is used in the treatment process at some works in the North East to remove naturally-occurring aluminium.
NITRATES - occur naturally from both mineral and soil processes and from agricultural activity; where present they are removed by sophisticated treatment or reduced to safe levels by mixing with low-nitrate water.
PHOSPHORUS - occurs naturally and in fertilisers and detergents; phosphate is added to treated water in some areas to protect the uptake of lead from domestic plumbing systems processes.
COPPER AND ZINC - presence is largely due to contact with domestic plumbing systems.
LEAD - treated water is virtually lead free; lead was used as a plumbing material and is still common in many older properties; we treat the water to make it less likely to absorb lead from plumbing but the safest way to deal with lead pipes is to replace them.
CHLORINE - small amounts are added to the water as it leaves the treatment works to kill any harmful bacteria present and to keep the water safe on its way to your tap.
FLUORIDE - occurs naturally in some sources; is added to some supplies in the North East of England at the request of the local health authority.
PESTICIDES - may be found in water from land that has been intensively farmed; where present they are removed by sophisticated treatment processes.
PAH (polynuclear aromatic hydrocarbons) - may result from the corrosion of the linings of old cast iron mains.
BACTERIA - if found they indicate that the water has been contaminated on its way to your home or as it passes through a dirty tap.