How do I know what size my shower head is?

If you’re looking to get a new showerhead, you might naturally be wondering if any showerhead will fit your shower arm—that pipe in your wall that connects your showerhead to your water supply. The good news is that for most homes, there is a straightforward answer:

Showerheads have a universal thread size in the United States and Canada, which is designated as ½-inch NPT. As a result, any locally sold showerhead should be compatible with your shower arm. The exceptions to this rule are showerheads sold in other countries, unconventional showerhead designs, or very old homes.

There’s so much more involved in selecting the right showerhead. To make sure that you don’t end up spending hours scouring the Internet or running back and forth from the hardware store, check out the details and tips I’ve compiled below to help you successfully choose a compatible showerhead.

Are Showerheads Universal?

As I mentioned earlier, the standard size for showerheads in the US and Canada is ½-inch NPT, but there are exceptions to that standard that should be kept in mind when replacing a showerhead.

1. Showerhead Sizes In Other Countries

If you’re purchasing online and find an amazing showerhead made in another country, be sure to look closely at the specs. In the US and Canada, the standard thread size is 1/2-inch NPT. The “NPT” stands for National Pipe Thread Tapered.

On the other hand, most countries around the world use a different pipe thread standard—BSP, which is an abbreviation for British Standard Pipe, and you’ll likely find it in Asia, Australia, Europe, New Zealand, and South Africa. A common showerhead thread size in these places is 1/2-inch BSP.

2. Unconventional Showerheads

In most cases, you’ll probably only find showerheads with the standard ½-inch NPT. However, you might come across some unconventional shower rigs that you’ll want to avoid.

And unless you plan on doing some remodeling and making major changes to your plumbing, then you’ll want to avoid this type of hardware.

For example, rainfall showerheads, designed to imitate falling rain, sometimes have a ceiling installation. If you have a wall-mounted shower arm, like most people do, a rainfall showerhead might be too large (the head itself, not the pipe threading).

While there are smaller rainfall showerheads that might work on the wall, you’ll have to consider the angle of the shower arm to get the rain effect you want.

3. Very Old Homes

While it is currently the standard to install pipes to fit a 1/2-inch NPT showerhead, that hasn’t always been the case. If you live in an older home, you might find that your showerhead is not compatible with the existing shower arm.

If you run into that problem, you might want to replace the shower arm or find an adapter if you don’t want to mess with anything in the shower walls.

One common problem that I’ve seen online is that some old homes have a ball end shower arm, which used to be made by only a few companies, such as Price Pfister, Gerber Ball, and American Standard.

Because it’s so old, you probably won’t be able to find any adapters in local stores, but there are adapters available online if you do a quick search for ball end shower arm adapters.

Hopefully you won’t fall into any of these showerhead sizing exceptions, but to be sure, let’s cover a few ways you can make sure you’re getting a showerhead that will fit your shower.

Tips for Checking the Showerhead Fit

As you prepare to dive into all your showerhead options, you’ll need to have a good way to double check that it’s going to fit your shower arm. That’s what we’ll cover here.

Tip #1: Take your old showerhead with you to the store

If you’re like me, you may stare at your shower arm and not have a clue as to whether it’s the standard size. In that case, it’ll save you a lot of time by simply removing and bringing your existing showerhead to the store.

If you don’t have the existing showerhead available, you can also remove the shower arm and bring it. That way, you can get help or test whether it’s compatible before having to make the trek home to try it out.

Tip #2: Measure your shower arm

If you live out in the middle of nowhere, buy everything online, or you’re not able to bring the existing parts to the store for whatever reason, you can double-check the threads of your shower arm by measuring it.

Male or Female Threads

First of all, take note as to whether your shower arm has male or female threads. Are the threads on the outside or the inside of the fitting? If your threads are on the outside, it has male threads. If they’re on the inside, it has female threads.

Male and female connect to one another, so if your shower arm has male threads, which is common, you’ll need to get a showerhead with a connector that has female threads and vice versa.

Tapered or Parallel

Next, you’ll want to see if your threads are tapered or parallel. If it’s tapered, the diameter will decrease along the threads. If it’s parallel, the threads maintain a consistent diameter. You should be able to tell by simply looking at it.

If you’re in the US or Canada, chances are that it’s tapered, but you’ll want to double-check and make sure that your connecting part matches since a tapered male part will connect with a tapered female part.

Inner and Outer Diameter

Now measure the diameter. For male threads, you’ll want to measure the outside diameter. For female threads, you’ll want to measure the inside diameter. These are often designated by “I.D.” for inner diameter and “O.D.” for outer diameter.

You’ll then want to take that actual measurement and compare it on a thread chart to find the nominal size or trade size. This nominal size (or trade size) is a standard naming convention to help identify parts.

These are the key measurements to take note of as you’re shopping for showerheads. I know, it seems like a bit much. Don’t be afraid to ask for help and clarification at the store.

If you need further measurements, here’s a handy guide for determining pipe thread type and pipe size.

Tip #3: Ask a friend

I live in a city and have no idea who I would ask if I had a plumbing-related question, but if I did know somebody, I would have no hesitations in asking for help.

If you are one of those lucky people who happens to have a friend or family member who is a plumber or someone who just knows a lot about plumbing, why not ask for some advice. It may end up saving you a lot of time and effort.

Tip #4: Buy a few different showerheads and return the ones that don’t work

To ensure that I get the correct sized showerhead, I personally would do any one of the tips above before resorting to this one.

If you don’t have the tools to measure, an expert to ask, and can’t get your current parts to the store, you can always buy several showerheads with different types of connections and sizes.

Try to connect them all to your shower arm and see what fits. I would be careful to make sure it appropriately fits without having to force it as some might be close in size but have different threads. You definitely don’t want your showerhead to leak!

Alright, while you’re shopping for hardware let’s also look ahead at the other supplies you’ll need.

The Other Supplies You’ll Need

In addition to a new showerhead, you might also need the following items to finish the job:

• An adjustable wrench or pliers to remove the old head and install the new one
• A rag to pad the inside of your wrench, to prevent damage to the pipe or showerhead
• Teflon tape (included with most new showerheads) to seal the connection

Related Questions

Can you change the showerhead in a rental?

You can usually change the showerhead in a rental, as long as there are no clauses in your lease regarding plumbing and fixtures. It would be wise to double-check with your landlord and get it in writing. If you do end up changing the showerhead, be sure to keep the old one in good condition, so when you move out, you can put it back in place in the same condition.

Do you have to turn off the water to change your showerhead?

No, you don’t have to turn off the water to the building in order to change your showerhead. However, you should definitely turn off the shower faucet to avoid getting soaked in water when you change your showerhead.

Are toilet seat sizes universal?

There are two standard sizes of toilet seats in the United States. They are elongated and round. Elongated toilet seats are 18.5 inches long and round toilet seats are 16.5 inches long. To find out what kind of toilet seat you need, measure from the end of the bowl to the middle of the seat post holes