Most outdoor faucets are fed by 1/2" pipe and have a 3/4" garden hose thread spout. To replace one, match three things: the pipe size, the connection to that pipe (solder, thread, PEX or push-fit), and for a frost-free faucet, the length, so its valve ends up inside the heated house.
What pipe feeds the faucet?
Look where the pipe meets the back of the faucet indoors, in the basement, the crawl space or behind an access panel.
Where are the threads on the pipe end?
Start overHow will you join it?
Start overThe inlet that fits
PEX inlet in your pipe’s size, matching your PEX joints
Crimp or clamp PEX (ASTM F1807) and expansion PEX (ASTM F1960, PEX-a only) use different inlets, made in 1/2" and 3/4".
On the package: Crimp PEX or expansion PEX, e.g. 1/2 in. crimp PEX
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The inlet that fits
CPVC glue-in or push-fit inlet
Some frost-free faucets have a 1/2" CPVC inlet that’s glued on. Push-fit inlets also take CPVC.
On the package: 1/2 in. CPVC, or 1/2 in. push-fit
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The inlet that fits
Female pipe thread inlet
Threads inside the inlet, to screw onto the pipe. Many frost-free faucets have 1/2" female thread inside and 3/4" male thread outside.
On the package: FPT (FIP) in your pipe’s size, e.g. 1/2 in. FPT
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The inlet that fits
Male pipe thread inlet
Threads on the outside of the inlet, to screw into the fitting. Standard hose bibs and many frost-free faucets come with a 1/2" or 3/4" male pipe thread inlet.
On the package: MPT (MIP) in your pipe’s size, e.g. 1/2 in. MPT
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The inlet that fits
Sweat (solder) inlet in your pipe’s size
A 1/2" sweat inlet takes 1/2" copper pipe inside it. Many frost-free faucets have a combination inlet, with male pipe thread outside and a sweat socket inside.
On the package: 1/2 in. MPT x 1/2 in. sweat, or 1/2 in. sweat
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The inlet that fits
1/2" push-fit inlet
Push-fit frost-free faucets go onto copper, PEX or CPVC with no solder or glue.
On the package: 1/2 in. push-fit
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Frost-free or standard?
A frost-free faucet (also sold as frost-proof or freezeless, or as a frost-free sillcock or wall hydrant) shuts the water off at the end of a long tube, several inches inside the house, where the heat keeps it from freezing. When you turn it off, the tube drains out through the spout. A standard hose bib shuts off right at the outside wall.
To tell which you have, look inside behind it. A long tube running through the wall to the pipe means frost-free. Where winters freeze, the plumbing codes don’t allow water pipe in an outside wall unless it’s protected from freezing, which a frost-free faucet does.
Frost-free length
The valve has to end up inside the heated space, with no insulation over the inlet. A.Y. McDonald’s rule: the faucet should be at least 2" longer than the wall is thick, and 6" or longer where winters freeze.
Makers don’t state length the same way. Woodford and Watts size their faucets by wall thickness (on a Woodford, the inlet adds its own length on top); Prier, Arrowhead and SharkBite list a length. Measure the wall where the faucet goes through, then check the maker’s chart before choosing.
| Maker | Sizes made | Sized by |
|---|---|---|
| Woodford (Model 17) | 4" to 24", every 2" | Wall thickness |
| Prier (C-144) | 1", 1-1/2", then 4" to 24" | Length |
| Watts (LFFHB) | 4" to 14" | Wall size |
| Arrowhead (460LF, 480LF) | 2" to 14" | Length |
| SharkBite | 4" to 18" | Length |
Backflow protection
The plumbing codes require a vacuum breaker on every outdoor faucet, so dirty water in a hose can’t be pulled back into the house’s water. Many frost-free faucets have one built in (listed to ASSE 1019) and need no add-on. A standard hose bib takes a screw-on hose vacuum breaker (ASSE 1011), made to stay on once it’s fitted; some come with it built in.
A built-in one isn’t meant to stay under pressure: makers limit it to 12 hours at a time, so don’t leave a hose timer or splitter on it.
Putting one in
- Shut off the water to the faucet (at its own shutoff valve if it has one, or the main) and drain the line.
- For a new hole, drill the size the instructions give: 1" to 1-1/4", depending on the maker and the inlet.
- Slide the faucet in from outside so it slopes slightly down toward the spout and can drain. Many have the slope built into the flange or come with a wedge.
- From inside, turn it until the maker’s mark shows the spout is pointing down: a line or date code pointing down, or the word TOP facing up.
- Flush the supply pipe, then connect it. Before soldering, open the faucet fully so the heat can’t ruin the seat washer; A.Y. McDonald also says to take the stem out of its sillcocks.
- Screw the flange to the wall, turn the water back on and check every joint for leaks.
Take the hose off before freezing weather. With a hose attached, a frost-free faucet can’t drain, and the tube can freeze and split inside the wall, where the leak may not show until you next turn it on.
Only fixing a leak?
Outdoor faucet leaking