Colour

What is Colour?
Colour in drinking water is caused by the interaction of light with suspended and dissolved particles. As these particles are likely to have colour of their own, the colour will appear higher if the number of particles is above an acceptable standard. Water that is treated should be clear, bright and free from colour with no abnormal change in its appearance. In the Drinking Water Regulations, it is defined as an Indicator Parameter.
What is an exceedance of the Colour parameter?
There is no designated limit for Colour in the EU drinking water directive, however, drinking water must be acceptable to consumers and no abnormal change in colour should occur.
How can an exceedance of Colour occur?
The presence of Colour in surface water is mostly due to the presence of dissolved organic matter from soil and decaying vegetable matter. Groundwater Colour can occur due to the presence of iron. In drinking water, change in Colour may indicate degradation of the water source, corrosion in the distribution system, or changes during the treatment processes.