Edwardian house in Edinburgh - now upstairs and downstairs flats. My mate lives downstairs. All cast iron drain pipes.
About 6 weeks ago there was a flash rainfall with hail and he discovered hail being washed up into his small bog room sink - he asked me to take a look sometime and today was that time. A bit of detective work had to be undertaken as the downpipe the sink drains into has been covered by the outside stair to the upstairs flat and there was an option that the sink flowed into another downpipe - various ploys plus some measurements showed that wasn't possible so we are pretty sure that it goes into the currently inaccessible pipe that also drains part of the roof and has outlets from the upstairs flat.
There must be a reason for the backup - seemingly what was the bathroom in the upstairs flat and had two discharge pipes into this downpipe, is now just a utility room with a washing machine.
Here's the question - is it likely that the low volume, possibly fibre laden, outflow from the washing machine is creating a build up in the drain pipe under the ground ? There is a downstream manhole nearby - will power hosing be able to clear an upstream blockage like this?
Rob