When I flush the toilet all seems normal but over the next few hours the water level in the pan drops significantly. The pan is not cracked or leaking so I assume the water must be going over the 'lip' and down the soil pipe, but why?
chech the manhole cover out side drains most likely blocked
erj
October 2009
Thanks very much John, it gives me somewhere to start looking. Andy
Andy Palmer
October 2009
When you use the other drains in the house, especially another loo, the vacuum caused in the soil pipe causes some water to be sucked out of the pan. This is either due to not enough ventilation to the SVP or the pipe itself having a blockage.
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