There are three kinds of social (nest building) wasps: 

Polistes    Hornets   Yellow Jackets

The most "wasp" looking of the wasp family, the polistes is a long, slender wasp with long, dangly hind legs. They build nests resembling an upside down umbrella, often under eaves.

The most docile of the social wasps, generally, if you leave them alone, they’ll leave you alone. So, if their nest is in an out-of-the-way location, you do not have to treat them. However, if their nest is in a location near people (over the front door or garage door, or a low part of the house where people frequent,) they should be killed.

There are good over-the-counter wasp aerosols that shoot a 10’ stream of insecticide that you could use. Of course, you could also hire a professional exterminator.

The polistes are the first social wasp to cause a problem in the spring. They are a heat loving wasp, and will "hang around" the sunny side of your house for several weeks prior to the time when they start to build their nests. At that time (beginning about mid-May) this activity will end on its own. Power spraying is ineffective during this "pre-nesting" period.

	The hornet is a thick, powerful looking wasp that is black and white in color. Their nest is the familiar looking football shaped nest, covered in a paper envelope with one entrance/exit hole near the bottom.
	This nest is usually in trees and bushes, but can also be attached to a house. They are very dangerous if their nest is disturbed! However, if the nest is in an out-of-the-way location, say, 25’ up in a tree, they can safely be left alone.

There are good over-the-counter wasp aerosols that shoot a 10’ stream of insecticide that you could use. Of course, you could also hire a professional exterminator.

Yellow-Jackets are the most aggressive and dangerous of the social wasps, and you should not attempt to self-treat them if they are nesting in a house.

They are often confused with ++bees,     

They are often confused with bees, as both are small and fast, with similar coloring. Yellow-Jackets are yellow and black, while bees are orange and black. The nests are rarely seen, as they are built in voids. This can be a hole in the ground, or a building void. The activity level as they enter and leave is so intense that you clearly know that there is a nest there.  They are usually not noticed until the end of July.

I repeat, do not try to self-treat Yellow Jackets in a building void, as you can create serious problems for yourself, such as forcing them into the house!

Yellow-Jacket nests should be exterminated wherever their nests are located!