Short definition

A hose bib is the threaded outdoor faucet mounted on the exterior wall of a house, used to connect a garden hose. Two main designs exist: standard (valve seat at the spout) and frost-proof / freeze-proof sillcock (valve seat moved into the warm wall cavity). On a standard hose bib, water sitting at the valve freezes and ruptures the line in PNW cold snaps — a top WA winter emergency call.

What it is

The body is brass or chrome-plated brass, with a 3/4-inch garden-hose thread on the outside and a 1/2-inch supply connection on the inside. Inside the bib, a stem with a rubber washer presses onto a brass seat to control flow.

On a standard hose bib, the valve seat sits right at the body — meaning the supply pipe inside the wall extends to the valve. When you close the bib in winter, water remains trapped at the valve, and any subfreezing temperature on the wall side ruptures it.

On a frost-proof sillcock (covered in its own entry), the valve seat is moved 6 to 24 inches inside the wall. Closing the handle drains the spout chamber to atmosphere through the body, leaving an empty and ice-safe spout.

Modern hose bibs include an integrated vacuum breaker that satisfies UPC backflow-protection requirements (ASSE 1011) — important when a hose-end chemical sprayer could otherwise siphon back into household supply.

Why it matters to a homeowner

The hose bib is the most predictable failure point in a Pacific Northwest house every November. A standard bib on an exterior wall, hose still attached, no insulation cover — the first hard freeze splits the supply pipe inside the wall. The leak doesn’t show up until thaw, and by then water has been running into the wall cavity for hours.

The fix is dual: detach hoses before freezes, and upgrade to a frost-proof sillcock at the next opportunity. Standard hose bibs run $10 to $25; frost-proof models are $30 to $80. Pro install runs $150 to $300 if the connection is accessible.

When a plumber says “you’ve got a burst sillcock” or “the hose bib split inside the wall,” they’re describing this fixture and this failure mode.

Common failure modes

  • Freeze rupture. Standard hose bib + subfreezing weather + water trapped at the valve = split pipe inside the wall. Discovery at thaw, often as a basement-ceiling stain. Top WA winter call.
  • Hose-attached freeze rupture. Even a frost-proof sillcock fails if a hose stays attached over winter — the air-lock prevents drain-back and traps water in the spout chamber. (See its own entry.)
  • Worn packing washer. Slow drip when running. Snug the packing nut or replace the packing.
  • Worn seat washer. Drip from spout when off. Replace the washer.
  • Cracked spout from impact. Lawnmower, ladder strike. Replace the bib.

Common variants

  • Hose bib vs. frost-proof sillcock. Different mechanism, very different winter behavior. The upgrade is universal in WA.
  • Hose bib vs. yard hydrant. Yard hydrants are buried-shutoff stand pipes for rural acreages.
  • Hose bib vs. boiler drain. Boiler drains look similar but are for water-heater service — not rated for outdoor use.

Washington note

Pacific Northwest freeze cycles make standard hose bibs a known liability. Every November cold snap produces a wave of “burst sillcock” calls across Seattle, Tacoma, Bellevue, and especially Spokane (which sees deeper sustained cold). The standard prevention sequence is: disconnect hoses by mid-October, drain bibs that don’t drain themselves, install foam covers for added margin, and budget for a frost-proof retrofit at any wall-opening opportunity. UPC, adopted in WA via WAC 51-56, requires backflow protection (ASSE 1011 vacuum breaker) on hose connections. Modern hose bibs include the vacuum breaker integrated; older bibs can be retrofit with a hose-thread vacuum breaker for a few dollars.