"NY" wrote in message
...
"Roger Mills" wrote in message
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A lot of cisterns don't have external overflows these days but overflow
into the pan. Bad idea if you're on a water meter because you're less
likely to notice that it's overflowing.

If they do it now (ie it's not contravening some safety regulation) I
wonder why toilet cisterns were *ever* made with external overflows, given
that the overflow pipe could always be connected by T piece into the
outlet pipe of the cistern to the pan - even in the days before flush-fit
cistern/pan connections.

I agree, though, that it makes it almost impossible to tell when the
cistern is overflowing and therefore that the ball valve needs some
attention.

Its not impossible, you can see it running down the back of the pan,
over the part of the pan that is above the static water level in the pan.