Is a Garden Hose 3/4 NPT? No. Here's the Real Thread Size

Quick answer: Is a garden hose 3/4 NPT? No. A standard US garden hose uses garden hose thread, officially 3/4-11.5 NH, which is a straight thread with 11.5 threads per inch that seals with a rubber washer. 3/4 inch NPT is a tapered pipe thread with 14 threads per inch that seals on the threads themselves. They look close but won’t seal together without an adapter.

The confusion makes sense. Both get called “3/4 inch,” and the outside diameters are within a few hundredths of an inch of each other. Screw one into the other and it may even catch for a turn or two.

Then it binds, or it leaks. That’s the giveaway.

When I read through the thread charts from Swagelok and a US gage maker, the answer was never in doubt. The details are worth knowing anyway, because they tell you how to fix the leak in front of you.

Why a Garden Hose Isn’t 3/4 NPT

They’re two different thread standards built for two different jobs. My take: think of one as a pipe thread and the other as a quick-connect for water. Here’s the side-by-side.

	Garden hose thread (GHT)	3/4 inch NPT
Official name	3/4-11.5 NH (National Hose)	3/4-14 NPT (National Pipe Taper)
Standard	ASME B1.20.7, hose coupling threads	ASME B1.20.1, general-purpose pipe threads
Threads per inch	11.5	14
Shape	Straight (parallel)	Tapered
Male thread diameter	About 1-1/16 inch (27 mm)	About 1.043 inch (26.49 mm)
Where it seals	A rubber or plastic washer in the female end	On the threads, with sealant

Three differences matter. The pitch is different, 11.5 versus 14 threads per inch, so the threads drift out of step after the first turn and never mesh properly no matter how hard you lean on the wrench.

One is straight and one is tapered. They also seal in different places.

How NPT Seals

Swagelok’s thread identification guide describes NPT as a 1° 47’ tapered thread with a 60° thread angle on both the male and female ends. The seal “is designed to take place on the tapered thread,” and Swagelok lists a sealant as required. As you tighten, the taper wedges the threads together.

How Garden Hose Thread Seals

Garden hose thread doesn’t wedge. It’s a straight thread, and the seal comes from a pliable rubber or plastic washer seated inside the female coupling. The threads just hold the washer tight against the end of the male fitting.

That’s why a leaking hose connection is so often a missing, flattened or cracked washer rather than a thread problem, and why a pack of replacement washers is the cheapest fix in the whole garage. Honestly, I’d check the washer before anything else.

What to Do Instead

If you need to connect a garden hose to an NPT pipe fitting, use an adapter. Don’t force the two threads together.

Brass adapters are made for exactly this, with 3/4-11.5 garden hose thread on one end and 3/4-14 NPT (or another pipe size) on the other. When you install one, here’s what I’d do:

Seal the NPT end the NPT way. Use thread sealant or tape on the male pipe threads, since NPT seals on the threads.
Seal the hose end the hose way. Make sure a good washer sits in the female hose coupling.
Hand-tighten the hose side. The washer does the work, so you don’t need a wrench there.
Turn the water on slowly and watch both joints for drips.

In practice, the most common mistake is wrapping thread tape around a garden hose thread and cranking it down hard to stop a leak. The tape isn’t what seals that joint. A fresh washer usually is.

How to Check: Is a Garden Hose 3/4 NPT or Hose Thread?

You don’t need special tools for a quick check. I’d start with your eyes and a ruler, though a thread gauge settles it fast if you have one.

Look for a washer. A female fitting with a rubber washer inside is almost certainly garden hose thread.
Feel for a taper. NPT male threads get slightly narrower toward the end. Garden hose threads stay the same diameter.
Count the threads. Lay a ruler along the threads. About 11 to 12 peaks in an inch points to garden hose thread. About 14 points to 3/4 NPT.
Check the markings. Adapters and fittings are often stamped or labeled with sizes like 3/4-11.5 or 3/4-14.

Don’t trust your eyes alone with imported parts, though. Swagelok notes that 1/2 and 3/4 inch ISO 7/1 (BSPT) and NPT threads can be hard to tell apart without precision tools. If you’re working with imported fittings, a thread gauge is worth borrowing.

1/2, 5/8 and 3/4 inch hoses use the same thread. Gage maker Ring & Plug Thread Gages says garden hose thread has only one base size, sold under six designations: 1/2, 5/8 and 3/4 inch, each in NH or NHR. All three hose sizes fit the standard outdoor faucet. The hose diameter and the thread size are separate things.

NH vs NHR. Ring & Plug explains that NH covers full-form threads that are cut or rolled, while NHR covers thin-walled parts. Same faucet, same fit.

NPSH hose ends. Some female hose fittings use a 3/4-14 NPSH thread, made to connect a hose to tapered pipe thread. If a fitting is labeled NPSH, it’s meant for pipe, not a standard faucet.

Outside the US. Hose fittings sold elsewhere may use other threads, such as BSP-based ones. Imported hoses and timers may need an adapter.

If you’re tracing a leak in a sprinkler line rather than a hose, the rules flip a little, and I think that trips up a lot of people. See how to fix a sprinkler head that broke off, where plumber’s tape does belong on the riser threads. More hose and irrigation guides live in our watering section.

Frequently Asked Questions

What thread is a garden hose in the US?

It’s 3/4-11.5 NH, also called garden hose thread or GHT. The thread is straight, has 11.5 threads per inch and measures about 1-1/16 inch across on the male end.

Will a 3/4 NPT fitting screw onto a garden hose?

Not properly. The pitch (14 versus 11.5 threads per inch) and the taper don’t match.

It binds or leaks. Use a hose-to-pipe adapter instead.

Do you need thread tape on a garden hose connection?

Usually not. A garden hose connection seals with the washer inside the female coupling. If it leaks, replace the washer first.

Is garden hose thread the same as NPS or NPSM?

No. Garden hose thread uses its own standard, ASME B1.20.7. Swagelok’s guide lists 3/4 inch NPSM at 14 threads per inch, the same pitch as 3/4 NPT, so it won’t mate with an 11.5-pitch hose thread either.

Are 5/8 and 3/4 inch hoses the same thread?

Yes. Ring & Plug Thread Gages says 1/2, 5/8 and 3/4 inch garden hoses share one base thread size and fit the same faucet.

Last updated: November 10, 2026. Sources: Swagelok thread and end connection identification guide (PDF), Ring & Plug Thread Gages: NH, National Hose and Garden hose thread standard (Wikipedia, citing ASME B1.20.7).