New guy with question regarding washing vinyl siding

I am concerned with doing pressure washing properly and, of course, without causing any damage to a customer’s house by way of not washing the siding correctly. So here is what I know and have been told: You need to be very careful to not force water up under the siding where it could get into the walls cause all kinds of problems due to water ending up where it’s not supposed to end up. This means making sure the water hits the siding at as much oif a 90 degree angle as possible. Only…

Every video I’ve watched or picture I’ve seen of vinyl or aluminum siding being washed shows it being done with the water hitting at an angle, not straight on or anything really even close to it. The latest example are a few videos I watched on youtube concerning use of an extension pole…unless you use an angle adapter, there’s no way that thing is going to direct water at the house at anything but, it would seem, an angle that is going to get up under the siding. So what gives? Thanks.

Its more a matter of the amount of pressure used that forces chem or water up under the siding and not the angle. As long as you use low pressure, the possibility of water and chem getting behind
the siding is reduced tremendously

Thank you. That was kinda what I figured, since those who make and install siding know very well this is something that is going to be outdoors all the time, and therefore has to be reasonably sealed against at least some moisture from under the slats. As my father told me when I started in the trades as a locksmith, one should usually stick with the overall principle of DON’T FORCE ANYTHING!