The way for using a pressure washer is to remove the debris found at the base of your downspout, and then put it in a trash bag. Then, direct a stream of water through the pressure washer, with a high GPM and through the downspout. When you find the water is running out freely from the downspouts, you can move on to the rest of the gutters.

Inspect the drainage of water during power washing. If the flow of the water is not free and is not helping your drainage system, then you must take care to clear the drainpipes from the existing obstructions.

When cleaning the gutter ensure that you clean the entire part of the gutter and not just a fraction of it. Cleaning only a part of it will not be fruitful and you will again have to clean it up shortly.