§ Dr. Jack Cunningham
To ask the Secretary of State for Environment, Food and Rural Affairs what statutory responsibilities apply to(a) owners of private water supplies and (b) local authorities to ensure that water supplied for domestic consumption meets legal requirements in respect of (i) lead content and (ii) coliforms; what action they are required to take to ensure that water supplies which fail to meet required standards are improved; and if she will make a statement. 
§ Mr. Morley
Any person who supplies water in connection with a commercial use is under a general duty of care to consumers, whether the supplier is a commercial supplier or is someone who offers occasional bed and breakfast facilities in their own home.
A local authority has a general duty to take steps to keep itself informed about the wholesomeness and sufficiency of water supplies, including every private water supply, to premises in their area. A supply is normally wholesome if it meets the standards set by the Private Water Supplies Regulations 1991, which include a maximum permitted concentration for lead and a standard of nil coliform bacteria.
Local authorities have a duty to monitor private water supplies at the frequencies set out in the Private Water Supplies Regulations 1991. Frequency depends on daily volume of supply or numbers of consumers. There is no statutory monitoring of private supplies that serve single dwellings solely for the daily domestic use of the occupants. Authorities prefer to advise such consumers informally where a supply is unwholesome.
Where a private supply is unwholesome, a local authority may serve a private supply notice, specifying remedial steps, or one or more "relevant persons". The steps may, for example, include installing a water treatment system, replacing lead pipework or taking protective measures at the source to prevent contamination. Such persons may be owners or occupiers of premises supplied by the private supply, or of premises where the source of the supply is situated, or persons exercising management or control in relation to the source.387W