John Rumm wrote:
mrcheerful . wrote:

glug when you emptied the bath or the basin/bidet. As long as you
have a continuous fall of as much as practical there will be no problems,


The maximum fall should be no more than 90mm / meter (and no less than
18mm). This is to prevent the siphoning problem that you observed, and
also to stop the water flowing away too fast and in the process
depositing any solid matter that was flowing with it.



That's useful info, is it the same for all wastes (loo, basin, etc) and
pipe sizes (50mm and 100mm)?

--
Dave S
(The return email address is a dummy)