Measuring the size of an outdoor faucet is important to ensure you get the right replacement faucet or accessories. Outdoor faucets, also known as hose bibs or sillcocks, come in different shapes and sizes. Here is a comprehensive guide on how to measure outdoor faucet size.
Introduction
When replacing an old leaky outdoor faucet or installing a new one, getting the right size is crucial for proper functioning. Outdoor faucets have different connector types and thread sizes that need to match up with water supply lines and accessories. Measuring the faucet inlet and outlet allows you to find the correct replacement part.
Properly measuring and identifying the faucet size also ensures compatibility with various attachments like hoses, splitters, timers, connectors, and more. Getting an inaccurate faucet measurement can lead to leakage, poor water pressure, and incompatible accessories.
This guide will walk through the key dimensions to measure, decoding thread sizes, tools needed, and how to measure speciality faucets. Follow the steps below to accurately determine outdoor faucet size for hassle-free replacement and accessory purchases.
How to Measure Faucet Inlet Size
The faucet inlet connects to the water supply line that brings water from the main plumbing into the faucet. This is commonly located at the base of the faucet body. The inlet size must match the supply line for a leak-free connection.
Follow these steps to measure the faucet inlet:
Step 1: Shut Off the Water Supply
Start by shutting off the shut-off valve that controls water flow to the outdoor faucet. This is usually located near where the supply line connects to the main plumbing. Shutting off the water prevents leakage while measuring.
Step 2: Disconnect the Faucet from Supply Line
Unscrew the supply line nut connecting the faucet inlet to the supply line using an adjustable wrench or pliers. You may need to hold the faucet body with another wrench to prevent spinning.
Disconnect the supply line so you can clearly see the faucet inlet.
Step 3: Identify Inlet Thread Type
Look closely at the faucet inlet and determine if it has straight/parallel threads or tapered/pipe threads. Straight threads are common on newer frost-free faucets while tapered threads are typically found on compression faucets.
Step 4: Measure Inlet Thread Diameter
Use a thread gauge tool, calipers, or tape measure to measure the outside thread diameter. Common sizes for outdoor faucets are 3/4 inch, 1/2 inch, or 3/8 inch. Record the thread pitch if using a thread gauge.
Step 5: Identify Inlet Connection Type
Note down the inlet connection type – male or female threaded, sweat fitting, or proprietary quick-connect. This ensures you get the matching connection on the replacement supply line.
How to Measure Faucet Outlet Size
The outlet size determines what accessories and attachments are compatible with the faucet. Hoses, valves, splitters, and timers attach to the outlet via threading, quick-connect, or special couplings. Measuring the outlet is similar to the inlet process.
Follow these steps to measure the faucet outlet:
Step 1: Remove Accessory from Outlet
If there is an accessory like a hose or splitter already attached to the faucet outlet, unscrew or disconnect it. Removing obstructions provides a clear view of the outlet for accurate measuring.
Step 2: Identify Outlet Thread Type
Examine the outlet threads to determine if they are straight or tapered just like the inlet side. The majority of outdoor faucet outlets feature garden hose threads.
Step 3: Measure Outlet Thread Diameter
Use a thread gauge, calipers, or tape measure to find the outside thread diameter. again, common sizes are 3/4 inch, 1/2 inch, or 3/8 inch. If using a thread gauge, note down the thread pitch too.
Step 4: Note Down Connection Type
Make note if the outlet connection is male or female threaded, has a quick-connect, or uses specialized coupling. Getting this right enables attaching compatible accessories.
Step 5: Check for Anti-Siphon Device
Finally, check if the faucet has an integral anti-siphon or backflow prevention device. This will be indicated by an additional opening or attachment point.
Decoding Thread Sizes
For both the inlet and outlet, you likely measured thread diameters like 3/4 inch NPT or 1/2 inch GHT. But what do these thread size labels mean? Here is a breakdown of common outdoor faucet thread size terminology:
- NPT: National Pipe Thread Tapered. Pipe threads that taper and seal with Teflon tape or thread sealant.
- NPS: National Pipe Thread Straight. Straight, parallel pipe threads that require gaskets/washers to seal.
- GHT: Garden Hose Threads. Special threads designed for connecting gardening hoses.
- MHT: Male Hose Threads. Standard hose threads on the male outlet side.
- FHT: Female Hose Threads. Standard hose threads on the female inlet side.
- Numbers: Thread diameter in inches – 3/4, 1/2, 3/8, etc.
- BSPT: British Standard Pipe Thread Tapered. UK version of NPT.
So a faucet marked 3/4 inch male NPT has 3/4 inch tapered inlet threads. And a 1/2 inch female GHT has 1/2 inch straight outlet threads for garden hoses. Matching up the thread types and diameters is key for compatibility.
Special Tools for Measuring Faucets
Some specialized tools can make measuring outdoor faucets quicker and more precise. Here are some recommended tools:
- Thread gauge – Has different thread pitches for identifying thread types and diameter
- Calipers – Measures interior and exterior dimensions like thread diameter
- Tape measure – A standard tape measure also works for measuring diameters
- Adjustable wrenches – For disconnecting supply line and holding faucet
- Flashlight – Illuminates inlet and outlet for better visibility
- Mirror – Lets you see backside threads on outlet
- Plumbers putty – Makes thread gauge/caliper seating easier for tapered threads
These tools are inexpensive and available at most hardware stores and home improvement centers. Having them on hand makes faucet measuring much simpler.
How to Measure Frost-Free Faucets
Frost-free, anti-siphon, and sillcock faucets have an extended shaft that is embedded deeper to prevent freezing temperatures from damaging internal components. This extended design requires a special measurement technique.
Follow these steps to measure frost-free outdoor faucets:
Step 1: Locate the Bonnet
Look for a circular bonnet nut mid-way down the faucet shaft. This covers an interior seal and is where you need to measure.
Step 2: Disconnect Water Lines
Shut off water supply and disconnect inlet supply line so you can manipulate the faucet.
Step 3: Loosen and Remove Bonnet
Use adjustable pliers or wrenches to loosen the bonnet nut and take it off the faucet shaft.
Step 4: Measure Bonnet Thread Diameter
With the bonnet removed, use thread gauge or calipers to measure bonnet thread diameter to determine inlet size.
Step 5: Measure Outlet as Usual
Follow standard steps to measure the outlet at the faucet spout end.
Step 6: Reinstall Bonnet and Connect Supply
When finished measuring, screw bonnet nut back on and reconnect supply line. Restore water supply and check for leaks.
This method allows you to get the correct inlet and outlet dimensions for frost-free faucets despite their long design.
Measuring Kitchen Faucets and Bibs
Kitchen faucets and pot filler bibs designed for indoor use can also be installed on outdoor walls or posts. Here is how to measure these indoor-style faucets:
- Remove faucet handle and decorations to expose the base screws.
- For single hole faucets, measure the hole diameter.
- For widespread faucets, measure the distance between handles.
- Measure the base thread diameter using thread gauge or calipers.
- Note down any special base designs like square or hex shapes.
- Measure the outlet spout size normally.
This will give you the required mounting hole size and thread diameter to match accessories to indoor kitchen-style outdoor faucets.
Measuring Commercial/Industrial Faucets
Commercial or industrial wall-mounted faucets have larger outlets designed for filling buckets and tanks. Follow these tips when measuring commercial faucets:
- Identify common commercial thread types like garden hose (GHT), fire hose (NST), or cam & groove couplings.
- Account for any adapters converting NPT pipe threads to quick-connect outlets.
- Use large caliper jaws or pi tape to measure over 2 inch outlet diameters.
- Note any backflow prevention built into the faucet.
Measuring commercial faucets ensures you get compatible industrial-grade hoses, valves, and accessories.
Connecting to Measured Faucet Size
Once you have carefully measured the outdoor faucet inlet and outlet, use that information to get the right replacement parts:
- Get new supply line with matching inlet thread type, diameter, and connection gender.
- Choose compatible accessories that have outlet threads, diameters, and couplings.
- For frost free faucets, use bonnet nut measurements for inlet compatibility.
- Select commercial accessories rated for faucet’s heavy-duty outlet size.
- Ensure any new faucet or hose bib has the same inlet and outlet sizes.
Taking precise measurements ensures everything connects and seals properly with the faucet’s threads and couplings for leak and burst-free performance.
Frequently Asked Questions About Measuring Outdoor Faucets
Below are answers to some common questions about measuring outdoor faucet size:
How can I determine faucet thread pitch?
Use a thread gauge tool that has different thread pitches labeled. Place on threads and match pitch visually. Or note number of threads per inch.
My outdoor faucet is leaking. How do I know what replacement to get?
First measure the inlet and outlet connections as described above. Then get a new faucet with matching threaded or quick-connect dimensions and thread types.
Can I measure faucet size without shutting off water?
It’s not recommended – removing lines and fittings with water still flowing will lead to leakage and inaccurate measurements. Always shut off supply first.
How do I get replacement supply lines and hoses for my measured size?
Most home improvement stores have replacement supply lines and garden hoses in common sizes like 1/2 inch, 5/8 inch and 3/4 inch to match standard faucets. Bring your thread measurements for other sizes.
My threads are corroded. What’s the best way to determine diameter?
Carefully clear any debris or corrosion with a wire brush first. You can also wrap plumber’s putty around thread to get an impression and then measure the putty.
How can I find compatible valves and splitters for my faucet outlet?
Match the outlet thread diameter, pitch, and type like garden hose threads (GHT/MHT). Also account for any quick connect or specialty coupling.
Do I need any special tools for measuring faucet sizes?
A basic tape measure and adjustable wrenches are sufficient, but thread gauges and calipers make measuring the thread dimensions more precise. Flashlight and mirror also help.
How do I measure a frost-free sillcock that is installed in the ground?
You need to dig around the sleeve down to the bonnet nut to remove and measure. If unable to dig, check above ground hose bib connections for compatibility clues.
Measuring outdoor faucet sizes properly is vital for finding the right matching replacement fixtures and accessories. Follow the guide above to accurately determine the inlet and outlet dimensions through thread types, diameter, and connection styles. Taking the time to measure precisely will ensure your new faucet and accessories install and function flawlessly.
Conclusion
Measuring outdoor faucet size accurately is crucial when replacing or installing new exterior water taps and sillcocks. Paying attention to key dimensions like thread diameter, thread pitch, thread style, connector types, and outlet configurations will ensure you get compatible replacement fixtures, hoses, valves, timers, and other accessories.
Use the detailed measuring steps and tips outlined above for standard and specialty outdoor faucets to get the correct replacements parts the first time. Taking precise measurements will prevent leakage, low water pressure, and component damage due to size mismatches. With the right tools and technique, determining outdoor faucet size is a straightforward process that anyone can do.