Hi We have a stand pip to drain the washing machine and it is fed into the wast pipe of the sink Just under the u-bend. It is a pukka kit type with its own u-bend etc.. This stand pipe is also fed with a stand pipe for the dishwasher. so it has been for 20 years or so.
Recently every now and again the washing machine water over flows the stand pipe. any suggestions as to how to prevent this. could i put a 'lid' on the pipe to stop it overflowing. I have checked for blockages.
Thanks
Gary