There are generally three different kinds of valve systems used in buildings that can control the flow of the water. Although all three work differently, each valve design does an adequate job and will generally promise a homeowner long-term satisfaction in maintaining a healthy plumbing layout.
Stop valves are a very basic, and extremely common, variety that utilize a rubber gasket located at a seat in the middle of the valve. These kinds of valves are usually only used in situations where water flow is generally weak, like sinks, toilets or other basic appliances. Essentially, when the valve is turned in the off position, pressure is put on a small metal tab that water can pass under when the valve is in the "on" position. When this tab is pushed against the rubber gasket, it completely stops the flow of water by creating a wall in the valve.
Another kind of valve, used for heavier-duty scenarios is the gate valve, also known as the full-flow valve. These valves employ a metal wall that goes down completely when the valve is turned in the "off" position. When on, the valve becomes an unobstructed pathway for water to pass through.
The third kind of valve that is popular in many plumbing systems is the ball valve. Like the gate valve, this design allows a full-flow scenario when turned to the "on" position. It features a stainless steel ball that has a hole drilled into it. When the valve is on, the hole is parallel to the flow of water, while it twists perpendicularly when turned off.
If a valve in your house springs a leak, contact an experienced Arlington plumber like one of those at John C. Flood to repair or replace the piece.