Hello Dave, I am also considering buying a Miele washer/dryer and like you looked at their online manual for interest and noticed that they don't recommend theuse of water softeners. We have a Kinetico 2020c HF water softener fitted to our hot and cold water. I don't understand why Miele say this, cos our water softener brochures go on and on about how much it will help with our laundry and they even show pictures of washing powder etc, so they must be happy with washing machines, its just Miele that isn't happy. I've spoken to two Miele dealers in my local area and they say it isn't a problem but won't give me a definitive answer as to why it should or shouldn't be a problem with Miele. I've today emailed Miele asking them for an explanation, so hope to get an answer, and if I do I'll let you know. Kindest Regards, Peter