Showers are a total fixture in modern bathrooms across the country but installing them can sometimes seem a bit daunting, as you may not know exactly what you do or do not need to consider when one is installed.

One question that many people have when it comes to installing showers is whether or not there needs to be a ‘Trap’, or what is often commonly referred to as a ‘P-Trap’, or an ‘S-Trap’.
This is the ‘U’-shaped part of the shower’s drainage pipe that you may not otherwise realize is there, because it is most commonly embedded deep within the floor.
So, does there need to be a trap when installing a shower? If so, why? If these questions are currently flooding your mind, then you will want to keep on reading down below, because we have compiled together everything you could need to know!
Do Shower Drains Need To Have A Trap?
Yes. All shower drains within the United States must have a trap installed, and this is required by law not only in the United States but across the world.
Most showers will automatically have these traps installed when they are fitted into the home, and all bathroom fitters must make a point of adhering to the rules on shower drains by law.
Why Do Shower Drains Need To Have A Trap?
The key reason why traps are required by law when installing a shower in the United States is that the trap is responsible for keeping hazardous gasses from rising into the home.
An appliance within the home that connects to the main plumbing system must have a trap, and this is because the gasses that build up in sewage systems can actually be very hazardous as well as just outright disgusting!
Some gasses like carbon monoxide and even methane can be produced in the sewage system, but much like most gasses, they travel upwards, which gives them a hard time navigating the design of a drainage trap.
If there is no trap then these gasses can easily seep into the home, which can not only produce an unpleasant smell but could be hazardous to health and may pose a risk of death, as gasses like carbon monoxide are silent killers!
How Do Shower Drain Traps Work?
Though the curved shape of a drainage trap may look very unassuming, the shape actually plays a key role in helping to keep your bathroom safe from gasses.
As we mentioned earlier, gasses travel upwards, subsequently, traps are installed to create a dip in the drainage system that anything traveling down the drains must navigate to travel onward.
This dip makes it impossible for gasses that may be traveling up through the drains to travel onward and find themselves rising into the bathroom.
The trap is installed in such a way that the curve points downward, which also has the extra benefit of trapping water.
The water is trapped in a way that causes the entire trap to be filled with water. Gasses from the drainage pipes cannot pass through water, thus the simple use of water can further help keep gasses from escaping the drains.
The water that is trapped in the trap does not simply stay there, and whenever new water is used in the shower it will quickly displace all of the water that is currently in the trap, meaning that the water is constantly being refreshed.
The bend of the shower drain trap also makes it impossible for animals and small insects to travel up through the drains, as they will find the bend too challenging to navigate, and the risk of drowning in the trapped water is too great.
Where Does The Shower Drain Trap Need To Be Installed?
The law stipulates that the shower drain trap cannot be further than 5 feet away from the actual shower drain inlet. However, where the trap is installed within that 5 feet is totally up to you.
However, generally, you will want to try and have the trap installed as close to the shower drain inlet as possible, as this helps to make the trap more effective.
The further a trap is away from the drain inlet, the less effective it is at trapping water, thus creating an airtight seal that keeps gasses from rising up. This could have the risk of making the bathroom smellier.

What Do You Do If A Shower Drain Trap Isn’t Working Properly?
You may occasionally find that your shower drain trap encounters some issues, and it can often be difficult to figure out just how you are supposed to go about fixing any such issues.
In some cases, you may even simply just need to clean out the shower drain trap. Let’s take a look at how to do it!
Use A Solution To Clean Out The Trap
If you suspect that your shower drain trap is blocked, then one of the best things you can do is to create your own drain cleaner to eat away at the dirt, clearing the blockage.
This is a great first option because it helps to save you the potential trouble of having to remove the trap outright.
In order to make an effective drain trap cleaner, simply take some baking soda and add a little bit of white vinegar.
Take around half a cup of baking soda, and pour it down the shower drain. Once you have done that, all you then need to do is follow it down with a cup of white vinegar.
This will create a slightly acidic solution that will travel down the drains and eat away at built-up dirt without proving too strong so as to cause damage to the surface of the pipes.
You don’t want to use drain cleaning solutions that are too harsh, as they may damage the PVC in the pipes
If the solution doesn’t prove enough, you may want to also make use of a tool such as a drain cleaner or a plumbing snake which can carefully travel down the length of the drains so that you can then carefully force built-up dirt to move, allowing the trap to work as normal.
This is another great solution because it allows you to be directly involved with cleaning, and can help you to get a sense of how bad the situation is within your trap.
Uninstall The Trap From The Drain
This should generally be your last recourse, as removing the drain trap can actually be very difficult, and may result in greater damage across the drains. Luckily, most drain traps can be uninstalled easily.
What you need to do is carefully remove the area of flooring that stands above the trap, and then carefully unscrew the trap from its position. Make sure that you position a bucket just under the trap to catch any water or dirt that may leak out.
Once you have removed the trap, you can ascertain what the problem is and then find an adequate solution.
If there is simply dirt built up in the trap, then scrub it clean, or allow it to sit in a cleaning solution for around 10 minutes before draining it with some fresh water.
If the trap looks damaged in any way, it is best to replace it, as damage could cause water to leak out from the trap, which keeps it from pooling water, which is what helps it to create a seal that keeps gasses out.
Once you are ready to reinstall it, make sure that you screw it firmly into place so that the water can begin pooling again, keeping your bathroom and your household safe.
If at any point you encounter difficulty while attempting to uninstall the trap from your drain, or you are ever in doubt at any point, make sure not to go any further, and call a local plumber to take a look at the issue for you, lest you run the risk of further damage to your drainage pipes.
Can Shower Drain Traps Dry Up?
Because shower drain traps depend on the use of water to create an air-tight seal that keeps gasses from seeping through, it is important to make sure that there is always an adequate supply of it within the drainage trap.
Over time, the water within the drain trap may evaporate, so it is important to make sure that you refresh the water every now and again.
We recommend running the shower for a few seconds at least once every week, in order to keep the water supply strong.
To Wrap Up
As you can now see, it is required by law for a shower drain to have a trap installed, as the potential risk to health of there not being a drain trap is very significant.
Drain traps help to keep gasses from sewage pipes leaking into the bathroom, as they create a vacuum seal through the simple use of water that travels through it.
It is very unlikely that your shower does not have a drain trap installed, as they are required by law, but if you find that your shower does not have one, then it is imperative that you have one installed as soon as possible for your own health.
To check if you have the trap installed, all you need to do is carefully remove the floor around the area of the pipe and check for the iconic bend of the trap.
If you do not have a drain trap installed, make sure to contact a local plumbing company to have one installed.
Frequently Asked Questions
The look of a shower trap can actually change from case to case. Some shower drain traps have a shape reminiscent of a ‘P’, while others have a shape reminiscent of an ‘S’. This all depends on where the trap is installed.
If the drain would benefit from more curves, then an ‘S’-shaped trap would be used. Either way, shower traps need to have that iconic curve in order to work efficiently.
Not only can a shower trap help to prevent harmful gasses from rising up from the sewers, but it can also help to generally stop smells from rising up from the drains.
Yes, a toilet and a shower can share a drain, but it is important that each device has its own trap arm to keep sewage gasses from rising up.
Without drain vents, gases will build up in plumbing pipes and drains and keep water from flowing freely. This will prevent air from leaving the pipes, causing backups, odors, clogged toilets and other problems
the distance between your trap and the vent should be no more than 6 feet. In other words, for the vent to work properly, it needs to feed into the drain line within 6 feet of the trapways that connect to it.
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