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What is a Sillcock Valve? Working, Types, and Replacement

Sillcock valve

The sillcock valve is a perfect solution for an outdoor water fixture. It takes water to the outside of a building and provides a threaded spigot to attach a garden hose or pipe. You can then use the water to water a garden or lawn, wash a car, and several other needs. Here’s what you need to know about this type of valve.

What is a Sillcock Valve?

A sillcock valve is an outdoor faucet, a fixture that protrudes from the wall of your home or other building. It lets you connect a garden hose or pipe to it and use your home water outside.

The sillcock derives its name from the installation height, just about that of the foundation sill. Some call it a hose bib, seeing that it’s a wall faucet that you connect a hose to.

The typical sillcock features a handle, stem, spout, mounting flange, and shut-off. Here’s more about these parts.

  • Handle – the sillcock valve handle can be metal or plastic. It controls the valves on/off
  • Stem – the stem connects to the handle to the shut-off mechanism
  • Spout – the spout opens the valve to the outside. It’s usually threaded to allow hose and pipe connection
  • Mounting flange – secures the valve to a wall using screws
  • Valve shut off – a washer mechanism that opens and closes the valve
Sillcock valve parts
Sillcock valve parts

How Does a Sillcock Valve Work?

The operation of a sillcock valve involves a simple washer shut-off located at the end of the stem. Here’s how it works:

  • Turning the handle to close the valve causes the washer to press against the inlet, stopping water flow.
  • Upon turning the handle for the “valve on,” the stem lifts the washer. The washer no longer closes the inlet, allowing water to flow.
  • The pipe that feeds the sillcock has a shut-off valve. The valve lets you stop water flow whenever necessary, such as in an emergency or maintenance session.
  • Some come with a vacuum break attached to them, which helps prevent backflow and the contamination that it could cause.
  • If needed to be freeze-proof, the valve has a long stem to set the shut off far back into the house.
Using a sillcock with a garden
Using a sillcock with a garden

What is a Sillcock Valve Used for?

A sillcock fixture is where you connect your outdoor hose or pipe. You can then use the water for any outdoor activity that requires water, such as:

  • Watering a lawn
  • Irrigating a garden
  • Washing a car
  • Getting water to an outdoor kitchen, adventure vehicle like camper, etc.
  • Washing windows and other surfaces
  • And any other outdoor application.
Frost free sillcock
Frost free sillcock

Types of Sillcock Valves

Different types of sillcocks are available based on their design. In light of that, you can choose from one of these types, usually depending on your location and preferred features.

Anti-Siphon Sillcock Valve

As its name implies, the anti-siphon sillcock valve prevents a reverse flow of the water flowing through it to the outside. It features a vacuum break, which is the knob seen on its upper side.

The anti-siphoning feature helps avoid contamination, as would happen if dirty water flowed back into the drinking water pipes.

In some regions, the anti-siphoning feature is a law requirement. If your local building codes require one, ensure the valve you buy has it.

Frost Free Sillcock Valve

The frost-free version features a long rod for the stem. The stem extends the valve shut off far into the warm interior of the building, and there’s no chance of water freezing inside during cold days.

If you live in colder climates, this is your best outdoor faucet; you will not need to worry about it getting damaged, even in the freezing conditions of the winter season.

The sillcock water valve today is usually a frost-free design. You can buy these in lengths ranging from about 6 to 12 inches.

Sillcock Angle Valve

The angled type is the standard version of the sillcock valve. It has the handle set at an angle of 45 degrees to the wall. Some people call it a hose bib.

The sillcock angle valve is suitable for use in warm climates. When installed, it has its on/off washer outside the wall and can get damaged in freezing temperatures.

If using one in cold climates, drain all water after use. Also, avoid leaving the hose attached after using it, as that can cause the shut-off to freeze.

Brass sillcock valve

Sillcock Valve vs. Hose Bib

You have likely heard the two names (sillcock valve and hose bib), used interchangeably, sometimes separately. So what is their difference, if any? When used independently, here’s what they mean:

  • The sillcock mainly refers to the frost-free type of valve with a long rod for the stem.
  • The hose bib is the standard version of the sillcock that comes with a shorter stem.
  • The sillcock valve handle also lies perpendicular to the wall after installation.
  • On the other hand, the hose bib handle makes a 45-degree angle with the inlet and outlet ports.
Sillcock valve replacement
Sillcock valve replacement

How to Replace a Sillcock Valve

After a long time, a sillcock can break down and stop working correctly. It may leak water, for example, or fail to bring any water to the outside. When that happens, it could be time to change it.

Replacing a sillcock valve takes a few steps and is something you can do yourself. Note that different types of this valve will also use varied connection methods, such as soldered or push-to-connect joints.

Below, we take you through replacing the copper-ended type of this valve. Here is how to go about it, including the required materials.


Sillcock Valve Replacement Steps

1. Find the shut-off valve near where the sillcock connects to a water pipe and turn it off.

2. Cut the pipe to disconnect the sillcock. Allow all water to drain

3. Outside, remove the screws that attach it to the wall.

4. Insert the new valve into the opening. Secure it using screws. Apply caulk to seal the opening.

5. Remove the sillcock stem. You don’t want soldering heat to damage the washer.

6. Measure and cut the coupling you need to connect the sillcock to the water pipe.

7. Using an emery cloth, clean the water pipe.

8. Apply soldering flux to all connections: the water pipe, coupling, and valve end.

9. Insert the coupling and solder the joint

10. Outside, reinstall the sillcock valve stem.

Once done, open the shut-off valve and test the sillcock for proper operation.

Sillcock Valve Replacement Tips

When installing the sillcock, tilt it down by a few degrees. To avoid damage, you want it to drain all water after use, especially during the cold season.

If connecting a galvanized steel sillcock to a copper pipe, use a dielectric transition material such as PEX. The dielectric will help prevent galvanic corrosion.

Before buying a sillcock, asses the types of pipes used in the plumbing. Ensure compatibility for material and connection method.


The sillcock valve provides convenience when you need to use water outdoors. You can also choose from various options, including quarter and multi-turn handles, frost-free designs, anti-siphoning vacuum breaks, and brass or stainless steel types. When buying one, ensure it fits your local climate and building code.

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