#1 a plain garden hose won't reach 20ft if you have pvc plumbing your water pressure may be too low. to make matters harder - you'd thing going up on a ladder would help (dangerous with a hose). as it turns out the water wants to go to about the same height whether it is in the hose or not. (meaning you will not get 10' extra reach going 10' up a ladder)

#2 you cannot pressure wash from the ground because you can only "soft wash" from ground (don't push water under the siding upward)

#3 you may need a gas powered if you expect sudsy water to reach that high without using a $120 wand or ladder

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