I would NOT NOT NOT power wash your house. Most likely, the original siding of your house is under the vinyl. As you can see, there are seams all over the vinyl. If you power wash, water will get under the vinyl - I think that's a guarantee. The siding may have been added because the original exterior was failing (or because that owner couldn't be bothered with painting). If your original siding is wood, you will most likely introduce mold and rot by the blasting of water under the vinyl and into the original wood. If your original siding is stucco, it will fail with the water. If the surface under the vinyl had already failed, and you power wash, I'd put out the welcome mat to having water introduced into the structure of your house.

Any chance you might take off the vinyl and restore the original exterior? You may be one of the lucky ones who finds that the original finish is in pretty good condition and restoration/painting will be fairly easy.

OK--If not power washing ,then what? My house looks really dingy. Thanks for the response I had heard that mostly too,that you should not power wash vinyl because of that behind the vinyl scene.But I still wanna know what people do to clean their vinyl houses. Anyone? Thanks,Jardinista

Dont listen, just powerwash it, I do mine all the time.

Aren't there different levels of power when power washing? Seems you could request a "gentle cycle". And have them spray with one of those spray tanks that are used with pesticides but fill it instead with soapy water (tsp? or spic 'n span?) first and then follow with a rinse with the gentle cycle from the power washer (or just a garden hose?).

IMO, wouldn't hurt to do two washes and two rinses, especially if it hasn't been cleaned in a while.

Also, maybe it would be a good idea to wait until summer during an 8 day forecast of sun and no rain to expedite the drying.

@ elphaba "Aren't there different levels of power when power washing?"

The terminology is tossed around very loosely. I bought a "power washer" at a yard sale. I had no delusions, it looked cheap and it was. I could adjust my hose to be more powerful.

A power washer can cause damage when being used by an inexperienced person. This is why you don't do it yourself or hire some kid or a guy that power washes on the weekends for extra beer money. This is your home (your largest) investment. The proper way to wash siding is to use a high flow machine (usually 5-8 gallons per minute)with low pressure. No more than 500 psi hitting the siding. A reputable cleaning contractor will rely on his cleaners to do most of the work. The right cleaners and equipment allow you to wash the siding without the use of high pressure. Washing vinyl with high pressure and at the wrong angles can force water behind the vinyl. Hire a professional that uses low pressure or soft washing methods. If he knows what he is doing, he will know what you're talking about. I can assure you, a house can be cleaned to restore it's appearance by using low pressure and the right cleaners.

Here is a link that might be useful: Exterior Cleaning Tips