Sillcock — definition, uses, identification, and replacement

A sillcock is the threaded outdoor hose faucet mounted through an exterior wall, also commonly called a hose bib.

Sillcock diagram — labeled parts, dimensions, and installation context

What It Is

The sillcock lets homeowners draw water outdoors for hoses, sprinklers, and general yard use. Many modern versions are frost-free, meaning the actual shutoff seat is located farther inside the wall.

Because it passes through the exterior wall, a sillcock has to be installed and pitched correctly to drain.

Types

Common types include standard hose bibs, frost-free sillcocks, vacuum-breaker sillcocks, and anti-siphon models.

Where It Is Used

They are used on exterior walls, garages, patios, and yards wherever a hose connection is needed outside the house.

How to Identify One

Look for the threaded faucet body projecting through the exterior wall with a hose connection at the front and a water line connected inside.

Replacement

Replacement is needed when the faucet drips, leaks inside the wall, freezes and cracks, or no longer drains correctly.

Sillcock — FAQ

What does a sillcock do?

A sillcock is the threaded outdoor hose faucet mounted through an exterior wall, also commonly called a hose bib. They are used on exterior walls, garages, patios, and yards wherever a hose connection is needed outside the house. In practical terms, it matters because the sillcock lets homeowners draw water outdoors for hoses, sprinklers, and general yard use. Many modern versions are frost-free, meaning the actual shutoff seat is located farther inside the wall.

How can I tell if the sillcock needs attention?

Water dripping from the spout, leaking around the handle, or moisture inside the wall after outdoor use are the big warning signs. Look for the threaded faucet body projecting through the exterior wall with a hose connection at the front and a water line connected inside.

Can a homeowner handle sillcock work, or should I call a pro?

Basic hose-bib replacement is manageable if the connection is exposed and accessible. Frost-free replacements with hidden connections are more likely to need a plumber. If the issue involves hidden leaks, structural support, code compliance, or specialty tools, professional help is usually the better path.

What should I match when buying a replacement sillcock?

Match the pipe connection, stem length, wall thickness, thread style, and whether an anti-siphon or frost-free model is needed. Taking the old part, measurements, or a manufacturer model number with you usually saves time and return trips.