5. Do you have an outside toilet or appliances in garages, sheds or outbuildings?

Most outside buildings, garages or sheds will not have been built with foul drains in place.  For some properties, especially those that are older, there may not be room for a washing machine in the kitchen.  In smaller kitchens any space for a washing machine may well now even be taken up by a dishwasher. 

In these situations it is possible that a washing machine might have been moved to an outbuilding, shed, garage or even onto a balcony with flats.  Check where any wastewater drainage goes to - it may well be misconnected into the nearest surface water drain causing pollution.