Our Milton Keynes station has been promised for 2 yrs.
Even though my TDS is silly high I worked out it would still be cheaper to produce water through twin DI then use spotless water.
My mate who lives in a flat though can’t wait for it to work as he has to travel 1hr round trip to get his water.
As others have said I don’t think it’ll have an impact as most get their windows cleaned out of can’t be bothered than necessity.
There are still window cleaners in areas where the TDS is around 30PPM. All the customers would need is a small Di and a pole. But they don’t bother. Same thing really.