What Is a Sill Cock Outdoor Faucet?

Sill Cocks

• A sill cock is simply any outdoor water faucet that sits on the exterior walls of a building. You may have one or more of these faucets mounted to the outside of your house, allowing you to attach a hose so you can wash your car or water your lawn or garden. The sill cock has a single spout and a single handle, which you turn clockwise to shut off the flow of water and counterclockwise to increase the flow of water. Different accessories, besides garden hoses, exist that you may attach to a sill cock faucet, such as a splitter that allows you to attach two hoses to the faucet at once.

Frost-Free

• Some newer sill cock faucets have a frost-free design, which keeps the water inside the faucet from freezing when outdoor temperatures dip below the freezing point. Frost-free sill cock outdoor faucets have a longer valve stem than other outdoor faucets, which keeps the water deeper in the water supply line so it sits inside the warmth of your house, keeping it from freezing when the faucet is not running. If your sill cock faucet does not have the frost-free feature, you must shut off the flow of water to the faucet before outdoor temperatures reach freezing; otherwise the water supply pipe may burst, leading to flooding inside your house.

Anti-Siphon

• An anti-siphoning device comes with some sill cock outdoor faucets, which keeps the water in an attached garden hose from siphoning back into the faucet. The water that has been sitting in the garden hose may not be clean. The anti-siphon device introduces a vacuum in the faucet, which keeps the water from flowing backwards and into your house’s plumbing. The anti-siphon device looks like a circular plastic cap on the top of the sill cock faucet. You may also purchase an anti-siphon valve that you screw into the faucet’s opening if your faucet does not already come with one.

Servicing

• Ignoring a leaking sill cock outdoor faucet wastes water, increasing your monthly water bill, and it can lead to major damage to your house once winter hits. The leaking water defeats the anti-freeze function of the faucet since water is present beyond the end of the valve stem, so the faucet or water pipe may still burst and cause flooding. To fix the faucet, you must shut off the flow of water to it, and then use a wrench to loosen the packing nut on the faucet’s assembly. With the packing nut loosened, you then can slide out the valve stem from the water pipe and remove the washer on the end of it. Installing a new, identical washer and putting the faucet back together will stop the leaking.