Water Supply and Treatment

Public perception is often that water supplies should be free! After all, the Company is only intercepting water that exists in the natural water cycle and supplying it to its customers!

In fact the abstraction of water from the environment and its treatment to ensure that it is safe to drink, is a technologically advanced process. It carries on for 24 hours a day, 365 days a year, so as to ensure that safe drinking water is always on tap.

In this section we outline the facilities which are used for abstracting raw water and the treatment processes which are used to convert it into drinking water.

River Itchen Water Treatment Works

Ariel View River Itchen Works (Custom)(1)At Gaters Mill the Company has its most complex treatment process. Although river water quality is good enough to support salmon and trout, it is not of a high enough standard to meet the stringent requirements needed for drinking water.

The location of the Company’s intake in the lower reaches of the River Itchen catchment results in wide variations in river water quality, sometimes as a result of surface run-off from fields and other water sources, but also from industrial and commercial discharges. As a result the Company has constructed Highwood Raw Water Storage Reservoir within the Itchen Valley Country Park. Here up to 135 million litres (about 3 or 4 days supply) can be stored.

The reservoir enables the Company to shut down its intake for short periods if the river water becomes excessively turbid (cloudy) or, alternatively, if pollution has occurred. Storage in the reservoir begins the treatment process by ensuring that many bacteria and viruses die out; it also smoothes out variations in quality thereby avoiding frequent changes to the treatment process at the Works.