What Is a Garden Hose Thread Called? Quick Answer

Introduction

If you have ever tried to connect a garden hose to a spigot, a sprinkler, or a pressure washer, you have likely wondered What Is a Garden Hose Thread Called? The short answer is that the standard thread used on most residential garden hoses in the United States is called Garden Hose Thread (GHT), also referred to as National Hose (NH) or 3/4‑inch GHT. Understanding this thread type, its dimensions, and how it differs from other common pipe threads can save you time, prevent leaks, and help you choose the right adapters for any watering task.

This guide covers everything you need to know about garden hose threads: the official name, the technical specifications, how to identify the thread on your equipment, compatibility concerns, installation best practices, common mistakes, and maintenance tips. A handy comparison table and a step‑by‑step identification guide are included so you can quickly confirm the thread type on any fitting.

Table of Contents

• What Is a Garden Hose Thread Called?
• History and Standards
• Thread Dimensions and Specifications
• Common Types of Garden Hose Fittings
• How to Identify Your Garden Hose Thread
• Compatibility Issues and Adapters
• Installation Best Practices
• Common Mistakes to Avoid
• Maintenance and Care
• Frequently Asked Questions
• Conclusion

What Is a Garden Hose Thread Called?

The thread found on virtually every residential garden hose in North America is officially designated Garden Hose Thread (GHT). In technical literature you will also see the abbreviation NH for National Hose, which is the same thread form. The thread is a straight (parallel) thread with a 3/4‑inch nominal diameter and 11.5 threads per inch (TPI). Because it is a straight thread, it does not taper like National Pipe Thread (NPT); instead, a rubber or plastic washer provides the seal when the male and female ends are tightened together.

Knowing the proper name is essential when you search for replacement parts, adapters, or when you need to communicate with a plumbing supplier. If you ask for a “garden hose thread” you will get the correct 3/4‑inch GHT fitting; if you mistakenly request a “3/4‑inch NPT” you will receive a tapered pipe thread that will not seal properly on a standard hose bibb.

History and Standards

The garden hose thread standard originated in the early 20th century when manufacturers needed a universal connection for lawn and garden equipment. The American Society of Mechanical Engineers (ASME) later formalized the dimensions under ASME B1.20.7, which defines the thread form, pitch, and major/minor diameters for GHT. The standard ensures that any hose, nozzle, sprinkler, or faucet labeled “GHT” will interchange reliably.

Internationally, other thread standards exist. The British Standard Pipe (BSP) parallel thread (BSPP) and the metric “G” thread are common in Europe and Asia. While they may look similar, their pitch and flank angles differ, so they are not directly compatible with GHT without an adapter.

Thread Dimensions and Specifications

Understanding the exact dimensions helps when you are machining custom fittings or verifying a part with a thread gauge. The key specifications for 3/4‑inch GHT are:

• Nominal size: 3/4 inch (19.05 mm)
• Threads per inch (TPI): 11.5
• Thread form: 60° included angle, truncated crest and root (UN/UNR style)
• Major diameter (external thread): 1.0625 in (26.99 mm)
• Minor diameter (internal thread): 0.9375 in (23.81 mm)
• Pitch diameter: 1.0000 in (25.40 mm)

Because the thread is straight, the sealing force comes from the washer compressed between the male and female faces. The washer is typically a 3/4‑inch rubber or EPDM gasket that fits into the female coupling.

Comparison of Common Thread Types

The table highlights why you cannot simply screw a GHT male end into an NPT female fitting: the thread pitch, angle, and sealing strategy are fundamentally different.

Common Types of Garden Hose Fittings

Garden hose connections come in several configurations, each using the same GHT thread but differing in geometry and convenience:

• Male hose end (MHE): External GHT threads on the hose itself; screws into a female faucet or adapter.
• Female hose end (FHE): Internal GHT threads with a washer seat; receives a male hose end or a male adapter.
• Quick‑connect couplers: Push‑fit bodies that lock onto a standard GHT male end; often used for frequent tool changes.
• Swivel adapters: Allow the hose to rotate without twisting the connection; useful for sprinkler heads.
• Y‑splitters and manifolds: One female GHT inlet with two or more male GHT outlets for multiple hoses.
• Pressure‑washer adapters: Convert GHT to the higher‑pressure M22 or 3/8‑inch quick‑connect used on pressure washers.

All of these rely on the same 3/4‑inch GHT thread for the primary seal, so any component labeled “GHT” will mate with any other GHT component.

How to Identify Your Garden Hose Thread

If you are unsure whether a fitting uses GHT, follow this step‑by‑step process:

1. Measure the outside diameter of the male thread with a caliper. A true 3/4‑inch GHT male measures approximately 1.0625 in (26.99 mm).
2. Count the threads per inch using a thread pitch gauge. GHT has 11.5 TPI; NPT has 14 TPI; BSPP has 14 TPI.
3. Check the thread profile with a thread gauge or by visual inspection. GHT threads have a 60° included angle with truncated crests, while NPT threads are tapered.
4. Look for a washer seat inside the female coupling. GHT female fittings have a flat seat for a rubber washer; NPT female fittings do not.
5. Read any markings on the fitting. Many manufacturers stamp “GHT”, “NH”, or “3/4‑GHT” on the body.
6. Test fit a known GHT male (such as a standard garden hose) into the female end. If it threads smoothly and a washer seals, it is GHT.

Completing these steps eliminates guesswork and ensures you purchase the correct adapters or replacement parts.

Compatibility Issues and Adapters

Because GHT is a straight thread, it will not seal against tapered threads such as NPT or BSPT without a proper adapter. Common compatibility scenarios include:

• Connecting a garden hose to a household faucet with NPT threads: Use a brass or plastic GHT‑to‑NPT adapter that has a GHT female on one side and an NPT male on the other.
• Attaching a European sprinkler (BSPP) to a U.S. hose bibb: A GHT‑to‑BSPP adapter with a washer on the GHT side and an O‑ring on the BSPP side provides a leak‑free joint.
• Joining two hoses of different diameters: A reducer coupling (e.g., 3/4‑inch GHT to 5/8‑inch GHT) maintains the same thread form while changing the hose bore.

When selecting adapters, choose materials rated for potable water if the hose supplies drinking water. Brass, stainless steel, and high‑grade polymer are typical choices. Avoid using pipe thread sealant (Teflon tape) on GHT connections; the washer provides the seal, and tape can prevent the washer from seating correctly.

Installation Best Practices

Proper installation extends the life of your hose and prevents water waste:

• Inspect the washer before each use; replace it if it is cracked, flattened, or missing.
• Hand‑tighten first, then give an additional quarter turn with pliers. Over‑tightening can deform the washer and strip the threads.
• Align the threads before turning to avoid cross‑threading, which damages both male and female components.
• Use a hose‑reel or hanger to keep the hose off the ground, reducing abrasion and kinking.
• Drain the hose after each use in freezing climates to prevent ice expansion from cracking the fittings.
• Store adapters separately in a dry container to avoid corrosion on brass threads.

Following these habits ensures a reliable, leak‑free connection every time you turn on the water.

Common Mistakes to Avoid

Even experienced gardeners can fall into these pitfalls:

• Assuming all 3/4‑inch threads are the same: NPT, BSPP, and GHT share a nominal size but differ in pitch and sealing method.
• Using Teflon tape on GHT: The tape fills the washer groove and prevents a proper seal.
• Over‑tightening with a wrench: This crushes the washer and can strip the relatively soft brass threads.
• Ignoring a worn washer: A deteriorated washer is the most common cause of leaks at the hose bibb.
• Connecting a high‑pressure washer directly to a standard hose bibb: The pressure rating of GHT fittings (typically 150 psi) is far below pressure‑washer output (2,000+ psi). Use a dedicated pressure‑washer adapter with a pressure‑rated hose.
• Leaving hoses pressurized in direct sunlight: UV exposure degrades rubber washers and softens plastic couplers.

Avoiding these mistakes saves water, money, and frustration.

Maintenance and Care

Routine maintenance keeps garden hose threads functional for years:

• Monthly washer check: Remove the female coupling, inspect the rubber washer, and replace if necessary.
• Thread cleaning: Use a soft brush and mild detergent to remove mineral deposits from the threads; rinse thoroughly.
• Lubrication: Apply a thin film of food‑grade silicone grease to the male threads once per season to ease assembly and prevent galling.
• Winter storage: Disconnect hoses, drain completely, coil loosely, and store indoors or in a heated garage.
• Inspect for cracks: Examine the hose barrel and coupling bodies for stress cracks, especially near the thread roots.

A small investment in maintenance prevents costly replacements and ensures consistent water flow.

Frequently Asked Questions

What Is a Garden Hose Thread Called?

The standard thread on residential garden hoses in the United States is called Garden Hose Thread (GHT), also known as National Hose (NH) or 3/4‑inch GHT.

Can I Use NPT Fittings on a Garden Hose?

No. NPT threads are tapered with a different pitch (14 TPI) and rely on thread interference plus sealant. They will not seal against a GHT washer seat. Use a GHT‑to‑NPT adapter instead.

How Do I Know If My Hose Bibb Is GHT?

Most outdoor faucets in North America are manufactured with a female GHT outlet. Look for a flat washer seat inside the spout and a 3/4‑inch external thread on the hose side. If unsure, measure the thread diameter (≈1.0625 in) and count 11.5 TPI.

What Size Washer Do I Need for a GHT Connection?

A standard 3/4‑inch garden hose washer (inside diameter 3/4 in, outside diameter 1 in, thickness ≈1/8 in) fits all GHT female couplings. Rubber or EPDM washers are recommended for durability.

Are Quick‑Connect Fittings Compatible with GHT?

Yes. Most quick‑connect couplers are designed to snap onto a standard GHT male end. The coupler body contains an internal GHT female thread with a washer, so the seal remains the same.

Can I Connect a Metric G Thread to a GHT Hose?

Direct connection is not possible because the pitch and flank angles differ. Use a GHT‑to‑Metric G adapter that provides a washer seal on the GHT side and an O‑ring seal on the metric side.

Why Does My Hose Leak at the Faucet?

The most common cause is a worn, missing, or incorrectly seated washer. Replace the washer, ensure the threads are clean, and hand‑tighten plus a quarter turn. If the leak persists, inspect the threads for damage.

How Often Should I Replace Garden Hose Washers?

Inspect washers at the start of each watering season and replace them annually or whenever they show signs of cracking, flattening, or loss of elasticity.

Conclusion

Understanding What Is a Garden Hose Thread Called? is the first step toward reliable, leak‑free watering. The garden hose thread—officially Garden Hose Thread (GHT) or National Hose (NH)—is a 3/4‑inch straight thread with 11.5 TPI that seals via a rubber washer rather than thread interference. By recognizing the dimensions, distinguishing GHT from NPT, BSPP, and metric threads, and following proper identification, installation, and maintenance practices, you can confidently connect hoses, sprinklers, pressure washers, and a wide range of accessories. Keep a spare washer on hand, use the correct adapters for non‑GHT equipment, and avoid common mistakes such as over‑tightening or applying thread sealant. With this knowledge, every outdoor water task becomes simpler and more efficient.