Why Can’t You Use PEX For Tub Spout Drop?

Imagine your plumber used PEX for the tub spout drop and you didn’t know. Everyone you know is telling you it is bad, even the strangers on the internet forums.

But why? Why can’t you use PEX for tub spout drop?

Using the wrong material at the wrong place (like PEX for tub sprout drop) can cause tons of issues in the long run. Bouncing off that, here is why you can’t use PEX for your tub spout drop.

Why PEX Isn’t Suitable For Tub Spout Drop

Tub Spouts Assembled Using Plastic Pex Piping

Since we got the basic requirements out of the way, let’s see why you can’t use PEX for your tub spout drop.

  • It Is Too Narrow

The tub spout drop should be wide enough to let the water flow. A narrow pipe will block the flow (or bottleneck it). This means your tub will take more time to fill.

The manufacturing companies recommend pipes with more than a ½” inner diameter for tub spout uses. Pipes with lesser diameters can act like bottlenecks and put pressure on the tub spout. The pressure can build up across the system and cause bigger issues.

PEX pipes are too narrow to use for tub spout drop. The inner diameter of the pipe is less than ½”. Therefore, manufacturing companies don’t recommend using PEX for tub spout drop. Sometimes they provide strict instructions to not use PEX for this.

Unless you can find a way of using a bigger PEX pipe for your tub spout drop, the regular ones are not recommended for your tub spout drop use. This leads to the next point.

  • Alternate Ways Are Too Complex

The instruction manuals tell you to not use regular ½” PEX pipes because they’re too narrow. What if you can find a bigger pipe? Can you make it work?

If you want to use a bigger ¾” PEX pipe for your tub spout drop, you’ll have to include some extra steps. Tub spouts can’t directly connect to a ¾” pipe. This means you’ll have to find a way of connecting the ½” outlet to your ¾” PEX pipe.

You’ll need to connect your ¾” PEX crimp to a ½” FIP drop-ear style elbow to hold the tub spout. Then you’ll need to work another ¾” PEX crimp to a ½” FIP adapter to where the valve is.

Connect the system with another ¾” PEX between them and you’ll have a working system.

The problem with this alternate mechanism is that it is too complex. You’ll need to work with more parts. It will still be risky because a small error in any part of the process means the entire thing is gone. Or worse, you’ll end up with a dripping tub spout.

  • It Isn’t Hard Enough
Pex Shower and Bath Plumbing

The pipes you use in your plumbing must be strong. The water running through them will put heavy pressure on the pipes. If they aren’t durable, you’ll end up with a pipe burst.

Copper is a more popular option for tub spout drops because it is durable.

The material is strong, so it holds up nicely against the water pressure. Fitting copper is easier because copper holds its place.

PEX materials are comparatively less sturdy. PEX pipes are too flexible, and it causes problems during fittings too. The pipe won’t hold its place because it is too flexible and shakes a lot.

With a material this shaky, you’re going to end up with a dripping tub spout. If you’re unlucky, the pipe can burst and flood your whole bathroom. It might even block other parts of the plumbing too.

Unless you’re okay with a burst pipe and worrying about it holding u against the water pressure, PEX is not suitable to use for your tub spout drop.

  • It Doesn’t Last Long

Plumbing is one of the internal components of your house. You’ll have to go through other layers of materials like your drywall and insulation.

This is why people choose long-lasting plumbing materials. They last long so you’ll have fewer issues to fix.

Tub spouts drop materials like copper take a long time to wear off. It is more resistant to water pressure and other external factors. Copper has a comparatively less corrosion rate and can be used anywhere.

PEX on the other hand is pretty quick to wear off. This is mostly because it does not deal well with water pressure. PEX is more corrosive than copper, so you’ll have to deal with more rust issues.

Your PEX tub spout drop won’t hold out better against external factors either. PEX can burst because of UV exposure and doesn’t do well with heat.

This means you can’t use PEX in places where the sunlight comes in. You can’t use PEX where hot water will come through because it isn’t good with heat.

General Features Of Tub Spout Drop Pipes

You can avoid facing issues later if you pick the right material for your plumbing need when you do it. Different outlets need different settings and materials. Here are the things your tub spout material must have.

Your tub spout drop must have an inside diameter big enough to maintain the water flow and not block it. The tub spout drop needs to be corrosion resistant and sturdy enough to hold its place.

The tub spout drop pipe must be resistant to external factors like UV rays so you can use them anywhere.

Frequently Asked Questions (FAQs)

Where should you not use PEX?

PEX doesn’t do good with heat and UV rays. You can’t use PEX in a place where sunlight gets in liberally. Since PEX materials can’t stand the heat, you can’t use them for hot water flow anywhere.
To put it straight, you can’t use PEX in any place where sunlight comes in. if there is heat involved, PEX isn’t suitable for that setting either.

Do rats chew through PEX?

Unfortunately, yes. As we’ve said, PEX materials are flexible and less durable. It is very easy for rodents to chew through this, and most houses with an attic face this problem.

Can I use a ¾” PEX for tub spout drop?

Yes, you can. PEX usually isn’t recommended because of the narrow inner diameter. The regular PEX has a less than ½” diameter, but a ¾” PEX doesn’t have that problem.
If you can get past the extra work, you can definitely use a ¾” PEX for your tub spout drop.

What kind of pipe do I use for tub spout drop?

You can use any pipe that is durable and easy to fit. The most common options for your tub spout drop are copper, galvanized pipe or brass. As long as it is durable and sturdy, you’re good to go with any material.

Can I use PVC for tub spout drop?

Not really. PVC is one of the least suitable materials for tub spouting drop. It isn’t durable enough most of the time it is just used as connectors, or in drain lines.


And here is the answer to why can’t you use PEX for tub spout drop.PEX isn’t durable, lasting, or wide enough to be used for your tub spout drop. You can use other materials like copper, brass, or galvanized pipes instead.

Whatever material you’re using, make sure it is compliant with the AHJ and instruction manuals you have. As long as it is durable and wide, you’re good to go.

Clyde Mitchell

I run a hardware store nearby Court Anaheim, CA. Over the last 7 years, I have been blogging about home improvement and yes, I own ReliefInBath.comFrom me and this website, you can expect some useful tips on great ideas for a modern bathroom.

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