What Size Is Garden Hose Thread: Standard Sizes Guide
In the US, garden hose thread is 3/4-11.5 NH (GHT), a straight thread.
You want fittings that don’t leak or bind. As a long-time DIYer and plumbing pro, I’ll explain exactly what size is garden hose thread, how it differs from pipe thread, and how to measure and match parts the right way. This guide covers standards, adapters, and hands-on tips so you can stop guessing and get watertight connections the first time.
The standard size: 3/4-11.5 NH (GHT) in the US
When people ask what size is garden hose thread, they are usually asking about the connector on a hose, nozzle, or spigot. In the United States, the standard is 3/4-11.5 NH, also written as 3/4 GHT. NH stands for National Hose. It is a straight thread and seals with a rubber washer, not with the threads.
Here’s what that means in practice:
- Size and form: 3/4 inch major diameter with 11.5 threads per inch, straight thread form.
- Seal method: A flat rubber washer in the female fitting makes the seal against the male face.
- Common use: Hose ends, nozzles, hose bibbs (outdoor spigots), Y-splitters, timers, and many filters.
Important: Hose size is not the same as thread size. Your hose may be 1/2 inch, 5/8 inch, or 3/4 inch inner diameter, but the thread on the ends is almost always 3/4 GHT in the US.
GHT vs NPT vs BSP: what fits and what does not
A lot of leaks start with mixing thread types. If you wonder what size is garden hose thread vs pipe threads, here’s the key: GHT is straight and uses a washer; NPT is tapered and seals by wedging; BSP is the British standard and is different again.
- GHT (3/4-11.5 NH): Straight thread, washer seal. Used on hoses, hose bibbs, nozzles.
- NPT (National Pipe Taper): Tapered thread, metal-to-metal seal with thread sealant. Used on plumbing pipes and fittings, like the back of a hose bibb inside the wall.
- BSP (British Standard Pipe, often BSPP for parallel): Common in the UK, EU, and Australia. Typical garden taps there are 3/4 BSPP, not GHT.
Do not force these together. They may start to thread, but they will not seal right and can damage parts. If you need to connect them, use the correct adapter, such as NPT-to-GHT or BSP-to-GHT.
How to identify your garden hose thread size at home
If you’re still unsure what size is garden hose thread on your gear, you can check it in minutes with simple tools.
- Count threads per inch: Use a thread gauge. GHT has 11.5 TPI. If you do not have a gauge, measure one inch along the thread and count about 11 or 12 ridges.
- Measure the outside diameter on a male fitting: About 1.0625 inches (1-1/16 inch), which is around 27 mm.
- Look for the washer: A GHT female fitting will have a flat rubber washer. If sealing depends on the washer, it is almost certainly GHT.
- Try a known-good part: If a standard US hose nozzle or Y-splitter fits and seals with a washer, it’s GHT.
Tip from the field: NPT feels tighter after a few turns. GHT usually spins on freely until the washer seats, then stops firmly.
Common hose and spigot sizes and how they relate
A classic point of confusion is hose diameter vs thread size. When you search what size is garden hose thread, you might see 5/8 inch and think that’s the thread. It’s not.
- Hose inner diameter: 1/2 inch, 5/8 inch (most common), or 3/4 inch for high flow.
- Thread on hose ends: Almost always 3/4-11.5 NH (GHT) in the US, no matter the hose ID.
- Outdoor spigot: The outside faucet usually has a 3/4 GHT male outlet. The back side inside the wall is pipe thread (often 1/2 or 3/4 NPT) and not the same as GHT.
If you change washers and tighten by hand until snug, you should get a drip-free seal. No wrench needed unless you are dealing with metal-on-metal faces, which is rare for GHT.
Adapters, fittings, and quick-connects you may need
Once you know what size is garden hose thread, shopping gets easier. You can add adapters to bridge systems and make swaps fast.
- NPT to GHT: Lets you connect a hose to a pipe-threaded outlet or device. Look for 1/2 NPT male to 3/4 GHT male or similar.
- BSP to GHT: Needed for UK/EU/AU taps to US hoses, or vice versa. Use a proper BSP-to-GHT adapter.
- Faucet-to-hose adapters: Convert indoor aerators to GHT. Check if your aerator is male or female and match the adapter.
- Quick-connect sets: Many have 3/4 GHT threads on the base. Choose brass for durability or polymer to reduce weight.
- Backflow preventers and vacuum breakers: Many screw onto a 3/4 GHT spigot and keep water safe.
Pro tip: Keep a pack of spare garden hose washers on hand. They are cheap and fix most leaks in seconds.
Troubleshooting leaks and cross-threading
A clean, square seal is the goal. If you ask what size is garden hose thread and still see drips, try these checks.
- Replace the washer: A cracked, missing, or hardened washer is the top cause of leaks.
- Hand-tighten first: Turn by hand until the washer seats. Use only a small wrench nudge if needed.
- Avoid Teflon tape on GHT: The seal comes from the washer, not the threads. Tape is not needed for sealing. A single wrap can help lubricate sticky metal threads, but it should not be relied on.
- Watch for cross-threading: If it feels gritty or jumps, back off and re-align. A mis-started connection will leak and can ruin the threads.
- Clean the faces: Dirt on the flat sealing face or washer will cause slow drips.
If two parts still will not seal, confirm they are both GHT and not NPT or BSP.
Real-world tips from the field
After thousands of hose hookups on jobs and at home, a few habits always pay off when figuring out what size is garden hose thread and making it work right.
- Use high-quality brass ends: Cheap thin brass or plastic deforms fast. Solid brass threads last longer and are kinder to gaskets.
- Swap to thick washers: I use extra-thick washers for old faucets with worn faces. It saves time and stops micro-drips.
- Label adapters: I mark NPT, GHT, and BSP with a paint pen. No more guessing in a hurry.
- Keep a short leader hose: A 2–3 foot leader with a swivel makes tight spaces easier and reduces stress on the main hose.
- Winterize fittings: Drain and store hose ends with the washers indoors. They stay soft and seal better next season.
These small steps reduce wasted water, protect threads, and keep gear working year after year.
Frequently Asked Questions of what size is garden hose thread
What size is garden hose thread in the United States?
It is 3/4-11.5 NH, also called 3/4 GHT. It is a straight thread that seals with a flat washer.
Is garden hose thread the same as NPT pipe thread?
No. GHT is straight and uses a washer. NPT is tapered and seals by wedging the threads with sealant.
What size is garden hose thread on a typical outdoor spigot?
The outlet is usually 3/4 GHT male. The pipe connection inside the wall is often 1/2 or 3/4 NPT and is not the same.
How can I tell what size is garden hose thread on my nozzle?
Measure the male OD at about 1-1/16 inch and count about 11.5 threads per inch. If it seals with a washer, it’s almost certainly GHT.
Do European or UK hoses use the same size as US garden hose thread?
Often not. Many use BSP threads, commonly 3/4 BSPP. You will need a BSP-to-GHT adapter to mix systems.
Should I use Teflon tape on garden hose threads?
It is not needed for sealing because GHT relies on a washer. You can use a light wrap for lubrication, but fix leaks by replacing the washer.
What size is garden hose thread for washing machine hoses?
In the US, washing machine hoses also use 3/4 GHT. They seal with a flat washer just like garden hoses.
Can a 5/8 inch hose have a different thread size?
The inner diameter is 5/8 inch, but the thread is still 3/4 GHT in the US. Hose ID and thread size are different things.
Conclusion
When you know that US garden hose thread is 3/4-11.5 NH (GHT), every connection gets easier. You avoid cross-threading, pick the right adapters, and fix leaks fast with a simple washer swap. Apply these tips today, label your fittings, and enjoy tight, clean seals all season. Want more guides like this? Subscribe for updates, ask a question, or share your own tips in the comments.
