Garden Hose Fittings Explained: Thread Sizes, Adapters and Leaks
Almost every garden hose, spigot and sprayer in the United States and Canada uses the same straight “garden hose thread”, usually written GHT or NH. It is not the same as the tapered thread on plumbing pipe, which is why a hose will not simply screw onto a pipe fitting. A rubber washer, not the thread, makes a hose connection watertight, so most leaks come down to a worn washer, a mismatched thread or a damaged coupling. This guide explains the terms, the adapters and a quick way to find out where a leak starts.
The Thread Almost Everything Uses
According to Wikipedia’s article on garden hoses, the US and Canadian standard is called garden hose thread, with the official designation NH for National Hose. It is a straight, non-tapered thread about 1 1/16 inches across with 11.5 threads per inch, used on hoses sold as 1/2, 5/8 and 3/4 inch. Male ends are sometimes labeled MHT and female ends FHT.
One point confuses many buyers: the “3/4 inch” refers to the size of the connection, not to the hose’s inside diameter. A 1/2-inch hose and a 3/4-inch hose can both end in the same 3/4-inch thread, which is why hoses of different widths fit the same spigot.
Many other countries use a British Standard Pipe thread, which is also nominally 3/4 inch but has 14 threads per inch. The two do not mate. Forcing a mismatched pair together damages the threads, and a connection that only looks close will leak or cross-thread. If you buy fittings from an overseas seller, or a hose imported from elsewhere, check which standard the listing means.
Fitting Vocabulary That Shows Up in Listings
| Term | What it means | Where you meet it |
|---|---|---|
| Male | External threads | Spigot outlet, nozzle inlet end of a hose |
| Female | Internal threads, usually with a washer inside | Hose end that screws onto a spigot |
| GHT, NH, NHT | Garden hose thread, straight, 11.5 threads per inch | Hoses, timers, sprinklers, nozzles, splitters |
| NHR | A thin-walled, rolled version of the 3/4-inch hose coupling | Often found on less expensive hoses |
| NPT | National pipe thread, tapered | Plumbing pipe and some filters and regulators; check the listing |
| BSP | British standard pipe, 14 threads per inch | Imported hoses and fittings |
| Hose barb | A ribbed tube that a hose slips onto and a clamp holds | Repair ends, drip and tubing connections |
| Quick-connect | A snap coupling that screws onto a threaded end | Hose ends, wands, sprayers |
Not every label is trustworthy. A listing that says “3/4 inch” on its own does not say whether it means hose thread or pipe thread. Look for GHT or NH in the title or the specification, and be wary when a fitting that is meant to mate with a pipe is described only by its nominal size.
Why a Washer Matters More Than the Thread
A straight thread does not seal on its own. In a hose connection the seal is a flat rubber or plastic washer inside the female coupling that is squeezed against the end of the male fitting. Some washers have a small mesh screen built in to catch debris. When the washer hardens, cracks, goes flat or falls out, the connection drips at the joint however tightly you turn it.
That makes washers the cheapest fix in the garden. Keep a bag of spares, replace one whenever a joint weeps, and check them when you take hoses and timers out of storage in spring. Winter is a good moment to inspect them too, as set out in our hose, timer and spigot winterizing guide.
Pipe Threads and Adapters
NPT is tapered: the threads narrow slightly along their length, about 1 inch in 16, and they seal as they are tightened, usually with PTFE thread tape or pipe dope. A garden hose thread is parallel and has no taper, so the two are different in how they seal as well as in size. A hose coupling will not seal on an NPT fitting, and an NPT fitting is not designed to take a hose washer.
Adapters solve this. A GHT-to-NPT adapter has a hose thread on one end and a pipe thread on the other. When you use one, treat the two ends differently: a rubber washer seals the hose-thread side, and thread tape or sealant seals the pipe-thread side. One guide to hose thread sizes puts it the same way. Use the right sealing method on each side instead of cranking the joint tighter.
Check which way the gender runs before you order. Adapters are sold as male-to-female, male-to-male or female-to-female, and one letter in the listing makes the difference between a part that works and a part that goes back. Brass and plastic adapters are both sold, and the listing should say which. Choose on how often you will connect and disconnect them, and on where the part will sit, since a fitting on a spigot carries the weight of the hose.
Before You Order a Fitting
- Name the thread on both sides. The listing should say GHT or NH for hose thread and NPT for pipe thread. If it does not say, ask or pick another.
- Check gender on both ends. Write down male or female for the part you have and the part it must join.
- Look for washers. A female hose-thread fitting should come with one, or the listing should say it is not included.
- Do not put tape on hose threads. It is for the pipe-thread side.
- Keep one brand of quick-connect. Connectors from different makers may not mate, so check before you mix them.
- Read the return terms. Small parts are easy to order wrong, and a seller with a clear return policy makes that cheap to fix.
Find the Leak
Work along the line, from the spigot to the nozzle. Turn the water on, dry each joint with a cloth, and watch which one wets first.
| Where it leaks | Likely cause | What to try |
|---|---|---|
| At the face of a female coupling when it is tightened | Missing, flat or hardened washer | Replace the washer and tighten by hand first |
| At the threads of a spigot or a fitting | Damaged or cross-threaded threads, or a mismatched standard | Unscrew, inspect the threads, and check both parts really are the same thread type |
| Where the hose meets its coupling | A loose or damaged coupling, or a cracked hose end | Cut the hose back and fit a repair end |
| At a quick-connect | A worn seal inside the connector | Check the seal, replace it or replace the connector |
| At an adapter on a pipe thread | Missing or poorly applied thread tape or sealant on the pipe side | Take it apart, clean the threads and reseal the pipe side |
Our hose quick-connect guide has more on how quick-connects wear, and our hose systems comparison compares complete hose setups. If the leak is at a splitter or manifold with several valves, the splitter and manifold guide covers those parts.
When to Repair a Hose End
If the washer is fine and the leak is where the hose enters the coupling, the fix is usually a repair end. Cut the damaged end off cleanly, slide in a replacement male or female end, and secure it as the kit directs. Read the listing for the hose inside diameter it fits, since hoses of different widths need different ends. If the hose has several leaks along its length, a repair may not be worth the effort. Be sure the hose is drained and stored properly in winter, using this winterizing guide, so splits do not start in the first place.
If you are comparing watering gear beyond fittings, our Watering & Irrigation page collects the hose, timer and sprinkler guides in one place.
Bottom line. US hoses use a straight 3/4-inch garden hose thread (GHT or NH) that seals with a rubber washer. Pipe threads (NPT) are tapered and seal with tape. Match thread types with an adapter, use the right seal on each side, and start any leak search with the washer.
Sources and verification
- Wikipedia (secondary), Garden hose: GHT and NH designations, thread form and 11.5 threads per inch, MHT and FHT, NHR, BSP at 14 threads per inch and its incompatibility, washers and mesh screens.
- Engineerfix, What is the standard garden hose thread size? (an explainer site): 3/4 inch refers to the connection, GHT is straight and NPT tapered, washer on the hose side and tape on the pipe side of an adapter, mismatches leak.
- Wikipedia (secondary), National pipe thread: NPT taper and sealing with PTFE tape or pipe dope.
- The leak table is a troubleshooting aid based on how these joints seal, not a manufacturer procedure. No pressure ratings or hose sizes are quoted. Check a fitting’s own specifications, and a hose maker’s instructions for repair ends.
Frequently Asked Questions
What thread size is a standard garden hose?
In the US and Canada it is garden hose thread, also written GHT or NH, a straight thread with 11.5 threads per inch. It is described as 3/4 inch, which refers to the connection and not to the hose’s inside diameter.
Can I screw a garden hose onto a pipe thread?
Not directly. Pipe thread (NPT) is tapered and seals with tape or sealant, while hose thread is straight and seals with a washer. Use a GHT-to-NPT adapter, and seal each side the right way.
Why does my hose leak where it screws onto the spigot?
The most common cause is a worn, flat or missing washer inside the female coupling. Replace the washer first. If it still leaks, check the threads for damage.
What does NH or NHR mean on a hose fitting?
NH stands for National Hose, the garden hose thread standard. NHR describes a thin-walled, rolled version of the 3/4-inch coupling, often found on less expensive hoses.
Do I need thread tape on a garden hose connection?
Not on a hose-thread joint, which seals with a rubber washer. Tape or sealant belongs on the tapered pipe-thread side of an adapter.