There are many types of valves used in a home.  Since they are used to control the flow, its a good thing to know what they look like, to label what work they perform in your home, and check them periodically.  Each type of valve works differently and their are always pros and cons to each type.   Most are used in the home to control the amount of pressurized water that is coming in from your city water or from your welll.  Some valves constrict the flow or shut it off entirely.  

Ball Valve

Gate valves are also to be used when the water needs to be “on” or “off”.   They are the most popular in plumbing valaves.  They control the flow of the water by raising or lowering and internal “gate” inside the product.  There is a knob at the top of the valve.  Since you could wera them out if you are using them “half way”.  This is not suggested.  They are common and reliable on the main supply and to the branch lines in a home.

Fixture Shutoff Valve 

Globe valves are used to regulate flow in plumbing applications. Globe valves are usually installed when the flow of water needs to be regulated or when it needs to be adjusted regularly. This sort of valve is raised or lowered by the valve knowvb. Inside it seals into a baffle to stop the flow of water. Globe valves are called this because they look globe-like or ball-like. Because globe valves are good for regulating flow, they are often used for the valves at outside hoses. 

Check valves typically are used in water tanks around the home.  Sometimes with other water storage tanks. They have an inlet where the water comes in and then an outlet where the water goes out.  Most of the time the water is traveling in one direction. On a water tank, a check valve allows pumped or pressurized water to come into the tank.  This valve does not allow the water to go back in.  This is similar to a backflow preventer.  

This type of valve is pretty important.  Sometimes homes are tied into high pressure water lines from the City.  If you have high water pressure, it can be hard on house hold plumbing and appliances.  High water pressure can blow faucets off sinks!  High pressure can hurt water heaters.  Having a pressure reducing valve in your home reduces the dangerous pressure to an acceptable limit.  They have a spring inside and a diaphragn that is adjusted to a certain limit.  They regulate and do not turn water flow on or off.  Water pressure-reducing valves are installed to reduce the water pressure to the desired or accepted limits. 

Butterfly valves are cool looking.  They have an internal disc that rotates to regulate the flow of water. Thewater flows around the disc, which is at the center of the valve, the water flow is reduced somewhat, even when the valve is fully open. If you want to control the rate of water flow, this can be perfectly with a butterfly. This valve should be watched and may require  maintenance after a couple of years. Butterfly valves are not that common in a home.  They are mostly used in commercial applications.