Lead in Drinking Water

Background

Lead is commonly found in the environment and comes from a number of sources such as vehicle exhaust and old paintwork. Lead can be present in drinking water due to dissolution from natural sources but the major source of lead in drinking water is from the metal dissolving in the water while it is in the service pipe. The service pipe connects the water companies water main to individual property or properties. Internal lead plumbing within a property may also contribute to lead in drinking water.

The amount of lead dissolved from the service pipe or internal plumbing depends on several factors such as pH, temperature, water softness and standing time of the water. Soft, acidic water is the most plumbosolvent.

The water company owns the part of the service pipe from the water main in the street up to the stopcock (usually at the boundary of the property), and is responsible for any work needed on pipes up to this point. Beyond this point, the pipework belongs to the owner of the property, who is responsible for its condition and maintenance. About 60% of properties are supplied through service pipes which do not contain lead, but there are still more than 7 million properties in England and Wales with lead supply pipes.

Lead can accumulate in the body usually in the skeleton. Infants, children up to 6 years of age and pregnant woman are the most susceptible to any adverse health effects from accumulation of lead. These health effects include the inhibition of a major enzyme in the production of haem (one of the constituents of blood) and the interference with calcium metabolism within the body. Lead is also toxic to the peripheral and central nervous system. More details on the health effects of lead accumulation in the body can be found on the World Health Organisation website.