Wholesome Water

Water companies are not merely expected to supply water — they are under a specific legal duty to ensure it meets a defined safety standard. Section 68 of the Water Industry Act 1991 provides that 'it shall be the duty of a water undertaker... to ensure that any water so supplied is wholesome at the time of supply', and, so far as reasonably practicable, to prevent deterioration in the quality of water from its sources over time. The word 'wholesome' is a defined legal standard rather than a general description — it is given detailed content by regulations made under the Act, principally the Water Supply (Water Quality) Regulations.

In practice, wholesomeness covers both health-related safety and consumer acceptability: water must not contain any microorganism, parasite or substance at a level that poses a danger to health, and it must also be acceptable in terms of taste, smell and appearance. The Drinking Water Inspectorate is the regulator responsible for checking that undertakers in England and Wales actually supply wholesome water and comply with the quality regulations, and it can require remedial action, or in serious cases refer failures for prosecution, where a supply falls short of the standard.