Water backs into shower after sink drains

[davidctid]

The water in my washbasin drains slowly but water with black particles now flows back into the shower. The smell is very unpleasant. This water eventually drains away after a while as long as no water is run into the washbasin.

I do not particularly wish to call out a plumber so has anyone any suggestions on how to resolve the problem.

There are no problems with the toilet and bath which are in the same room.

Thanks in advance

[SWPainting]

Your waste pipefor your bath will lead directly into the waste pipe for your hand basin and in turn leads to either your toilet waste or out to a separate down pipe.

By the sounds of it you have a blockage after your hand basin. Short of taking your pipework appart you could unscrew your u-bend behind your basin and push a rod down the pipe and hopefully get it round the 90 degree to the blockage. It sounds as though the blockage is after this 90 degree bend.