What is a frost-free sillcock?
Updated August 2026
A frost-free sillcock is an outdoor faucet built on a long stem so the valve that actually stops the water sits 6 to 12 inches inside the heated wall instead of out in the cold. Turning the handle operates a washer at the far end of that stem. Once it closes, whatever water remains in the exposed tube runs out the spout, which is the entire point, because an empty pipe cannot burst. Stems come in 4 to 14 inch lengths, matched to wall thickness and to how far the pipe must reach to find warm space.
Where it is
From the yard, a frost-free looks like an ordinary hose bib with one tell: a longer body where it enters the siding and a handle canted slightly upward. The real difference shows inside. Find the pipe stub in the basement, crawl space, or garage ceiling directly behind the spigot and you are looking at 6 to 14 inches of tube ending in a packing nut. That run has to pitch downhill toward the outside, roughly 1/4 inch per foot, or the tube holds water and the freeze protection exists only on paper. Anti-siphon models add a vacuum breaker cap on top of the spout, a separate $6–15 part.
What it does
The stem does one job well and fails one specific way. Leave a hose screwed on through a freeze and the tube cannot drain, so trapped water expands and splits the copper 8 inches back inside the wall. Nothing happens all winter. Then the first time you open the valve in April, water pours into the wall cavity behind finished drywall while the spigot outside looks perfectly dry. Owners often run it for weeks before spotting a damp band on a basement ceiling or catching a musty smell, and by then the repair takes in drywall, insulation, and sometimes framing. A gentler failure is the packing nut: water weeping around the handle while the faucet runs means a quarter turn of tightening or a new washer, and that leak at least shows itself outdoors.
Maintenance
Two things every fall, before the first hard freeze. Unscrew every hose and store it, then open each spigot for 10 seconds to confirm it drains and closes dry (outdoor faucet winterizing). An insulated foam cover is worth $3–8 on a north-facing wall and worth nothing if a hose is still attached. Come spring, run the faucet wide open while somebody watches the pipe indoors for the first 30 seconds, since that is when a winter split declares itself. Replace the stem washer once the handle needs extra force to stop a drip (why hose bibs leak). The hose bib checklist and your home maintenance checklist hold the seasonal pass, and leaving a hose connected in winter prices the shortcut.
What it costs to replace
A replacement frost-free sillcock runs $30–60 for the sillcock, $150–350 installed, and $1,000–4,000 more if a split one soaked a wall cavity first.
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Frequently asked questions
How do I tell whether my spigot is frost-free?
Two checks. Outside, a frost-free has a longer body at the wall and a handle angled upward rather than straight out. Inside, follow the pipe: a frost-free continues 6 to 14 inches into the building before you reach the packing nut. The clearest evidence comes during use, when a frost-free keeps dribbling for 5 to 10 seconds after you shut it as the tube empties itself.
Do I still need to close the indoor shutoff in winter?
Not if the sillcock is truly frost-free, pitched correctly, and hose-free. The exceptions are common enough to check for: a bib installed dead level or sloping back into the house, and any bib served by pipe in an unheated garage or crawl space. In those cases, close the interior valve and leave the outdoor spigot open so the section between them drains completely.
Water poured into my basement the first time I used the spigot. What happened?
The stem tube split during a freeze, nearly always because a hose stayed connected. Water only reaches the split when the valve is open, which is why nothing leaked all winter. Close the interior shutoff now, open the spigot to drain it, and leave it out of service until a plumber replaces the sillcock for $150–350. Then get the wall cavity dried within 48 hours so it does not turn into a mold job.
Why does water spray from the top of the spigot?
That is the vacuum breaker, the anti-siphon cap fitted to most sillcocks sold in the last 30 years. Its internal seal hardens with age and sprays sideways whenever the hose is under pressure. A repair kit costs $6–15 and takes 5 minutes: pop the cap, pull the plastic insert, press in the new one. The faucet itself is fine and needs nothing else.