tarquinlinbin wrote:
Went to assist a friend last night who had a crisis with a flood
through the ceiling. Found a concealed wc cistern behind a panel. The
water level was too high and was reaching the overflow. Unfortunately
the overflow exited the cistern and then ran uphill so that it exited
through the wall to outside a good 8 inches higher than the cistern!.
Result-the cistern just filled up and overflowed over the top.

Must be one of those new anti gravity cisterns.


Maybe the installer left some instructions with the householder:

'In case of overflow ensure someone is sucking at overflow pipe end'