Len
The stories I've heard from respected colleagues but not yet from a water authority, is that the problem is not our green or most regular solutions, but the soil we take from our customers carpets

When you think about it, they will take a worst case scenario. There could be blood or other pathogens in the carpet. We do come across some terrible stuff in ouir working lives that we are asked to remove from carpets and other textiles. To allow them to pass untreated into a watercourse or the ground our food grows from would be totally irresponsible.
I also gather that we're not really allowed to wash our cars and allow the water to run into storm drains. Certainly Car Wash facilities have to make other arrangements.
Finally, it was suggested to me in all seriousness, that in our commercial operations, we shouldn't be allowing fresh tapwater to be tipped onto land as this contains chemicals used in making the water hygenic, beneficial to our teeth etc. etc.

I firmly believe that the authorities have these regulations knowing that the householder isn't going to polute excessively, but they have the powers in place to take swift action if any person or busininess is creating an unacceptable problem.
A final finally. Many years ago, the water authority visited every home in our village. Fish were dying in our local stream/river. The problem turned out to be a (relatively) few householders who had had washing machines and dishwashers fitted which had been drained incorrectly into a storm rather than a foul drain. I was one of the guilty parties. Although everything was done amicably, all the offending householders were rightly given 14 days written notice to get things put right. The River Arrow through Alvechurch is now fine

Safe and happy cleaning

Ken