The American coffee shop chain Starbucks has been accused of wasting more than 23 million litres of water each day because staff are told to leave taps running non-stop.

A Starbucks executive revealed running the tap non-stop stopped breeding in the taps. [Agencies]

The bizarre policy, which is aimed at preventing germs developing in the taps in its 10,000 stores worldwide, has outraged environmental groups.

Every Starbucks branch has a cold tap behind the counter providing water for a sink called a "dipper well" used for washing spoons and utensils and the staff are banned from turning the water off under "health and safety rules", an investigation claims.

In a letter to a customer who complained about the waste, a Starbucks executive revealed that a constant flow stops breeding in the taps.

It means that 23.4 million litres of water - enough to fill an Olympic swimming pool every 83 minutes or sustain the population of drought-hit Namibia - is wasted every day.

In the UK alone, where there are 698 branches open for 13 hours a day, it counts for around 1.63 million litres of water wasted.

It raises questions about the Seattle-based company's much-hyped environmental credentials and will embarrass its legion of celebrity patrons.

Water firms say the policy harms the environment, while hygiene experts dismissed the health and safety-motivated policy as "nonsense" and "bonkers".

A spokesman for UK Water, which represents water companies, said it was "wasteful and unnecessary".

"There is absolutely no need to keep taps running," he said.

Peter Robinson, of Waste Watch, the environmental charity, said: "Leaving taps running all day is a shocking waste of precious water. And to claim you are doing it for health and safety reasons is bonkers.

"Tap water comes from rivers and groundwater and wasting it can cause great harm to the environment and wildlife. Big companies should set an example."

Jacob Tompkins, of Water Wise, said that provided the firm was undertaking all the usual cleaning processes, such a step was unnecessary.

"The chance of a build-up in the spout is extremely remote," he said. "And if there is one, they're not cleaning the tap properly."

A spokesman for Starbucks said the company's water usage adhered to the World Health Organization, United States Environmental Protection Agency, and the European Union directives.

She said: "The dipper well system currently in use ensures that we meet or exceed our own and local health standards.

"Dipper wells use a stream of continuous cold fresh-running water to rinse away food residue, help keep utensils clean and prevent bacterial growth."

However, she added: "We recognise the opportunity exists to reduce our total water usage. Starbucks' challenge is to balance water conservation with the need for customer safety."

(China Daily via Agencies October 7, 2008)