This is the time of year we see a lot of HOA violations concerning mildew on the side of houses. According to information from DR Horton, Mildew is the visible result of a type of fungus growth. All fungi propagate microscopic spores, which float through the air, and after landing on a hospitable surface, germinate. Fungi feed on organic matter- wood, paper, leather, plastic, or paint. Fungus decomposes and eventually will destroy the surface on which they are growing on. Often mildew is thought to be growing on paint, but is actually growing on a surface film which has collected on the paint, instead of the paint itself.
There are many species of mildew, differing in color, growth habits and other characteristics. They develop in warm, humid or shady locations. To identify mildew, dampen a cloth or sponge with common household bleach, such as Clorox or Purex. Apply it to the discolored surface. If the bleach caused the surface to lose its dark color, a good cleaning is in order. If you notice mildew forming on the house it is a lot easier to clean it when the first signs of it appear then when it has taken over the side or back of the house.
There are many over the counter cleaners that are available at any hardware store or you can make your own solution, mixed as follows:
1- cup Non phosphate detergent ( Tide)
1 qt. 5% sodium hypo chlorite ( Clorox or Purex )
3 qts warm water

Apply solution to siding using a pump sprayer and wait ten minutes. Scrub with a brush and rinse thoroughly, repeat as necessary.