Reports in the media that DIY plumbing inspired by TV makeovers is flooding UK rivers with sewage and killing fish is a bit of a red herring probably to detract from the real causes of river pollution.
I worked in the water industry for many years and have a 30 years long-service certifcate and letters thanking me for exceptional work over and above that normally expected. I also have memos from management to staff saying that the accepted practice of deliberately polluting rivers was no longer acceptible. This regular deliberate polluting of rivers on a large scale by the industry had been going on for years, before the memos were issued and continued for years afterwards. Contact with other area water authorities showed that deliberate pollution of rivers by them was widespread and fish kills were reported in the media downstream of the deliberate polluting from sewage works. It is hard to imagine the circumstances in which anyone would be able to connect a washing machine or other appliance to a drain which is not connected to a sewer which then flows to a sewage works for treatment. Very few houses have watercourses nearby to discharge waste into. New toilets can only be connected to a soil pipe because of the diameter of the pipes. The only case I have ever seen was from an automatic washing machine installed in a tent for a month on a campsite and the occupiers killed some fish in a beck. This is called wild camping. Living in France for over 20 years until recently and being a fisherman I found the rivers there of generally better quality and contained far more fish than they do in the UK. We ate all the fish we caught whatever size and it did not deplete the stocks.
Hove Edge, Brighouse