Valves are a vital part of the plumbing system.  We don’t think about them until we need them.  Sometimes 5 or 10 minutes of thought beforehand can be the difference between a puddle of water and a flood.  It is important to know where your main water shut off valve is in case you need to shut off the water to your home because of a burst pipe or a leak at a fixture.

  • Individual Fixture Valves – These valves isolate each fixture so that water does not reach the fixture when the valve is closed.  This allows an individual appliance to be installed or repaired.  You should have one valve on the toilet, two on each sink, and one on the ice-maker line.
  • Main Valve – The main valve shuts off the water for your entire house.  Various fluids will all have their own main valves (gas, propane, etc).  These must be used with extreme caution because a house that has filled with unburned natural gas or propane is a serious fire hazard.  Usually in the event of a gas leak, the sooner you can get out of your house and call the fire department and/or gas company, the better.
  • Ball Valves – The trick to understanding ball valves is simple: “When the handle and pipe are inline, fluid flows fine.”  There are many types of ball valves, but typically ball valves are simply used to shut off water flow.  A ball valve features a ball in a socket.  A cylindrical tube is hollowed out of the center of the ball so that when the tube inside is parallel with its input and output pipes, water flows freely, and when the ball is rotated 90°, flow stops.  Ball valves are typically controlled by a handle on the outside of the valve which is parallel with the hollow tube in the ball.
  • Butterfly Valves – Butterfly valves are quarter turn valves just like ball valves which means that they open and close in the same positions as ball valves.  (When the handle and pipe are inline, fluid flows fine.)  The difference between ball and butterfly valves is internal.  A butterfly valve has a disc inside of the pipe which can either stop flow when it is rotated perpendicular to the pipe, or allow flow across both sides of the disc when the valve is open.
  • Check Valves – Check valves stop or “check” the flow of fluid.  They come in various shapes and sizes with different types of internal stops, but in general they force fluid to only flow in one direction.  This keeps waste water from flowing back to where it came from, etc.
  • Pressure Relief Valves – Pressure relief valves are emergency fail-safes.  If pressure becomes to great or too low, pressure relief valves will open to let fluid or air in or out.
  • Pressure Reducing Valves – Pressure Reducing valves are usually bell shaped valves.  These valves have industrial applications, but they can also be used in the home to reduce city water pressure to something more manageable or to reduce water usage in general.  Obviously if water is coming out of the faucet at a lower pressure, then after a given period of time less water will have been used.  Using less water can have environmental and financial benefits.
  • Gas Valves – Most gas valves do three things.  First, they modulate the flow of gas based on a knob or dial on the valve.  Second, they modulate the flow of gas based on a thermostat’s electrical signal.  (The more gas burned the hotter the water in a water heater, etc.)  Third, they receive an electric signal from a pilot light.  If the pilot is on, it heats up a piece of metal called a thermocouple.  This makes the thermocouple send a small amount of electricity to the gas valve.  If the gas valve does not sense that the pilot light is on, it will stop the flow of gas so that the building does not fill with gas.  A house full of unburned gas is a fire waiting to happen.