On Thursday, 31 August 2017 07:49:09 UTC+1, N_Cook wrote:
Since the recent Coverack inundation and finding an archive newspaper
ref to a similar event ,locally , 60 years ago.
Where we are the problem is roof-run off rain getting into the sewer
system , from thousands of older houses, then the sewer system directly
under us going to a large sewage works, that cannot handle such
inundations, and all backs up rainwater and sewage.
I assume 4 inch/100mm sewer pipe screw-enlarge test bungs would be too
large for the first bend of bog-pan traps.
Kids plastic beach ball perhaps , firmly pushed down there and cut to
remove later perhaps.
Sink and bath plugs weighted down with anything heavy , but how to
temporarily block off sink and bath overflow holes? any other ideas?

Our local council has fitted something with a flap inside our main rain water drains around here to stop the river coming back uphill when we are close to flooding. I would have thought something similar would do the job.

Jonathan