what a waste of pure water!!
been cleaning since 2005 , we have made a proper connect hose very Professional and very quick connect , we have used water that is nearly 500ppm with no problems at all, don't understand what hot water has to do with it.
but at the end of the day if you won't to use pure , and you won't to waste all that money hay ho!
I do this sometimes, I’ve got a long length of pole hose connected to a male hose lock connector.
This sits in the van, but every now and then on a filthy first clean (or when doing facias and gutters) it comes out, connects to the customers hose and hey presto.
I then go over the windows with pure water so they dry as normal.
Daz it diesnt effect the windows, remember we’re going back over the windows quickly with the pure after, to get rid of all the hard water. It works perfectly and also has the bonus of high flow rate from the customers tap.
Granted, rarely do I bother doing first cleans like this. Just on the odd occasion when it’s really really filthy. But i always do facais and gutters with the customers water.