Plumbing Valve Basics: Water Shut-Off Valves

Stop or throttle the flow of liquid or gas with end-of-line valves

Plumbing Valve Basics: Water Shut-Off Valves

End-of-line valves are commonly used indoors on appliances, washing machines and furnaces, while outside they can be found on garden hose faucets and irrigation systems.

This guide highlights the different types of end-of-line valves, along with their materials, connections and applications.

Types

End-of-line valves fall into three broad categories: indoor, outdoor and general purpose.

See the tables for a breakdown of valve types and their uses.

Indoor Valves

Type Application Function and Points to Consider

Boiler drain valve

  • Washing machines
  • Water heaters
  • Boilers
  • Drains water and sediment
  • May be used with both hot and cold water
  • Removes waste water and empties it into a floor drain
  • Sizes: ¾” or ½”

Radiator/hydronic valve

  • Radiators
  • Baseboard heaters
  • Provides water balance and flow control to heating systems
  • May use either steam/hot water or gravity-fed hot water
  • Sizes: ½”, ¾”, 1”, ¼”

Water stop valve

  • Toilets
  • Faucets
  • Controls water running to one fixture only
  • Usually installed as a single stop valve for a toilet and one each for cold and hot water for a faucet


Outdoor Valves

Type Applications Function and Points to Consider

Sillcock

Garden hoses

  • Provides water to garden hoses
  • Frost-free sillcocks are ideal for climates with freezing temperatures
  • Some areas require the sillcock to have a backflow preventer
  • Sizes: ½” or ¾”

Yard hydrant

Garden hoses

  • For use in large yards
  • Connects to water line 1’ too 10’ below ground

Garden valve

Sprinkler systems

  • Has large openings and provides a high flow rate
  • Designs include bent nose for installation against a wall and inverted for use with a riser
  • Sizes: ½”, ¾”, 1”

Irrigation valve

Irrigation systems

  • Made from brass or plastic
  • Anti-siphon valves prevent backflow
  • Valve size may differ from pipe size
  • Requires both control and emergency shutoff valves
  • Sizes: ½” to 4"

Hose bibb

Hoses

  • Controls water flow
  • Supplies both hot and cold water
  • Available in different sizes and designs
  • Can be mounted horizontally to a wall or tank
  • Sizes: ½” or ¾”

Materials and Connections

If you’re replacing a valve, take note of how the valve connects to the pipe or line so you can be sure to buy the right one.

  • Metal valves connect using threaded male or female connections, solder or compression fittings.
  • Plastic valves can be glued to plastic pipes.
  • Old broken valves can cost you money over time in leaks, and some leaks can be hazardous, as is the case with natural gas.