Why do homes in the UK have separate hot and cold taps?

Traditionally the hot tap is on the left and the cold on the right in the UK

British homes have certain quirks which can puzzle people from overseas. Why are there separate taps for hot and cold water? Why are there pull cords instead of light switches in bathrooms? And why are there wheelie bins outside front doors? We asked the experts to answer these questions from curious visitors.

Why are there separate taps for hot and cold water?

"I've always wondered why you have two taps completely separated from each other in the same sink," asked Claudio Marongiu, 28, from Italy. "You burn or you freeze, it seems like there isn't another choice."

Batool Fatima, 36, who moved to Cheshire from Pakistan six years ago said she had not warmed to the idea and it had been hotly debated in family conversation.

We asked Kevin Wellman, chief executive officer of the Chartered Institute of Plumbing and Heating Engineering.

"This tradition dates back to a time when hot and cold water were kept separate to prevent contamination through cross connection," he said.

Mixer taps are the norm in the US and continental Europe

"Cold water came from a mains supply and was fit for drinking. Hot water would be serviced by a local storage cistern often situated in the loft.

"This caused an imbalance of pressures which meant that if incorrect taps and valves were installed one stream of water could force its way across to the other."

Water bylaws prevented hot and cold water being mixed because water that had been sitting in a tank in the loft was not deemed safe to drink, he said.

As far back as 1965 a code of practice called CP 310 advised that wherever possible hot water taps should be placed on the left.

"One of the reasons to maintain that over the years was reported to be so that the visually impaired would always know which sides the hot and cold were on," said Mr Wellman.

"When mixer taps came into vogue there was still a requirement to make sure water didn't mix until it came out of the tap," he said.

"So if you look closely you might be able to see the hot coming from the left hand side and the cold the right."

Why do bathrooms have string as a light switch?

Tourists may be puzzled as to why the British pull a string from the ceiling to turn on the light in the bathroom.

Fahmi Othman, 26, from Malaysia, asked us to enlighten her about this British quirk that baffled her on annual visits to the UK.

John O'Neill is technical engineering manager at NICEIC, a registration body for the electrical contracting industry.

He said: "In the UK we follow British Standard Requirements for Electrical Installations.

"These consider the bathroom to be an area of increased risk because the body could become immersed in water in the bath.

"The body's resistance to electricity drops significantly when immersed or partially immersed in water.

Pull cords were introduced because of the "perceived risk" of electric shock

"We judge it more likely that contact with live electrical parts would likely increase the effect of an electrical shock, and under some circumstances shocks could be fatal.

"It's not about having wet hands because you can have sockets and switches in the kitchen - it's about immersion. You should not be able to be in the bath and reach out and switch anything on.

"Pull cords are allowed because you cannot come into contact with the switch."

Mr O'Neill said other countries allowed power sockets and switches in their bathrooms but it had nothing to do with a difference in voltage.

"It's about perceived risk and the regulations in place in this country," he said.

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Why are there bins outside front doors?

"Why is it that outside every beautiful home on every street in the UK there's garbage bins standing out like the pride and glory of every home?" asked Stephanie Taylor Jamal, 46, who moved to Watford from Bangalore in India.

She said although rubbish overflowed on the streets in some parts of her home city, wheelie bins were kept out of sight at home.

"This is such a beautiful country - to find these bins so carelessly tossed right in front of homes - the quaintness of the town or city is lost," she said.

The rise in recycling is to blame for the UK's "bin blight" according to a report by the National House Building Council

Elizabeth Shove, professor of sociology at Lancaster University, told the BBC: "Having bins relates to the institutionalization of rubbish collection which is likely why they are kept outside."

The 1848 Public Health Act introduced the first municipal household refuse collections. At this time people burned their rubbish and deposited the ash in ashpit privies in the back yard wall for collection.

"By the 1900s, ashpits were no longer capable of handling household wastes," according to a paper co-written by Ms Shove. "Their fixed location in backyard walls made collection arrangements inflexible and the small capacity made it unsuitable for higher volume wastes."

Metal bins in the 1950s gave way to large plastic bins in the 1960s and these were put outside the front of houses for bin collections by road.

Homes in areas with a high population may not have outside space at the back or sides for bins to be stored, leaving residents no choice but to keep them outside their front doors, said a National House Building Council report into "bin blight".