I have never regretted putting low maintenance vinyl siding on my house in 1985. Low doesn't mean zero. I am now having problems with algae on the North side. It is the perfect environment, shaded and damp, and the ancient red wood deck doesn't help either. A few years ago I spent a hard day's work scrubbing it off with bleach and soap. If somebody assured me a pressure washer would easily take it off, I would buy one. I am sure once I had a killer app to make it worth while buying it, I would find many other uses for it.

If you don't have experience removing algae from vinyl siding, please don't waste my time with guess work.

I have the same problem on the corner of my house, My power washer along with a little SIMPLE GREEN cleaner does the trick.

Water Down Some Clorox In A Bug Sprayer And Spray It Down Then Hose It Off

Yep,

Bleach water; more bleachy than water should do it. I've never used a pressure washer though. I was afraid that the bleach may eat the rubber. I always ssloshed it on and let it work for about a minute and then scrubbed with a brush and rinsed it all off.

Just be a bit careful with the bleach. I find to do a nice job do that whole side to match to color brightness. Just stuck my nose in guys.

Always test a spot first its worth the safety look reasons

Signed 21 Boat

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While I would say many folks have used bleach in the past it is not the recommended chemical for this project. You can buy a household mildewcide house cleaner at most home centers. This is more likely green mold rather than a true algea. A pressure washer is good to flush the surface and rinse but you must kill the roots with a chemical. Do not use any pressure washer over 2200 psi on vinyl siding if you want to keep it attached to your home.