Plastic Cone Valve

• This type of valve has a cone-shaped handle. Installed on lower-grade water heaters, the valve breaks easily and is prone to leaking.
  
  

Plastic Faucet Valve

• This plastic valve has a round handle that turns to open and/or close the valve.
  
  

Brass Hose Bibb

• This is a durable brass valve whose handle turns to open and/or close that also resists freezing. Its main function is as a hose Bibb, but is often adapted for use on water heaters.
  
  

Gate Valve

• Gate valves installed on water heaters are designed to fully open or close. The valves have two stem types, risers and non-risers. The difference in the two are risers provide visual indication of the valve's position by the stem rising. Non-rising types are used in areas with constricted space, as the valve stem does not rise.
  
  

Brass Ball Valve

• This ia valve with a body made of brass or zinc, with a brass ball inside that is opened and/or closed by moving a lever 90 degrees. It offers the most flow and is the least likely to clog.