Iron

What is Iron?
Iron occurs naturally in the environment Iron and has many domestic and industrial uses including supplements to prevent deficiency, in food colouring, iron and steel products as well as in the water treatment process in the form of Ferric Sulphate. Some older watermains are made from cast iron and may corrode to give the water a rust coloured appearance which may not necessarily pose a health risk but would not be acceptable in terms of taste or appearance. In the Drinking Water Regulations, it is defined as an Indicator parameter.
What is an Iron exceedance?
A drinking water exceedance is a result from a drinking water sample which is above the acceptable limit. The limit for Iron in drinking water is 200µg/l, therefore any result that is greater than this is seen as an iron exceedance.
What causes an Iron exceedance?
The main cause of Iron exceedances in drinking water is due to disruption of Iron sediment in old cast Iron mains. Iron exceedances can also occur when small amounts of Iron-based coagulants (e.g. Ferric Chloride or Ferric Sulphate) that are used in some water treatment processes, are carried over from the treatment stages and can be found in drinking water.