On Thu, 28 May 2009 09:36:55 +0100, Michael Kilpatrick wrote:

Furthermore, whilst I might occasionally leave a tap running in a
basin, it's rather a different matter to leave an ascending spray bidet
running inadvertently and unattended, which is when a risk of
backsiphone might be present.

You might be using the bidet when Fireman Sam comes along and attaches his
water pump to the hydrant down the road, dropping the pressure to your
house and sucking the water and unmentionables back out of your pipework
into the common main. Then Sam turns his pump off and Mrs Jones down the
road finds she can fill a glass of water again ...

You might (fairly reasonably) say what are the chances of that happening,
but from the point of view of the makers of the regulations, if there
weren't such a restriction and, say, ascending spray bidets became popular
and common over the country there could be a pretty good probability of it
happening from time to time. And given the consequences (Mrs Jones isn't
too healthy and if she gets topped by the public water supply someone's
head's going to be on a pike) it's a reasonable position for the regulators
to say: "this water supply, provided at public expense, is intended to be
safe for drinking under all circumstances: if you want to wash your botty
in it, fine, but you must make doubleplus sure - at your expense - that
your botty washings don't get back into the public supply".

--
John Stumbles -- http://yaph.co.uk

Many hands make light work. Too many cooks spoil the broth.