The shower P-trap looks like a U-shaped section of a drain pipe hidden under the floor. Its main function is to prevent sewer pipe gases from entering the bathroom. All shower drains by law must have P-shaped traps, and if you do not have this, then you are endangering your family.
Does a shower drain need a P-trap?
In many countries of the world, including the USA, the presence of a P-shaped trap for a shower drain is mandatory. The P-shaped trap helps prevent terrible gases from entering the shower.
And also, thanks to its shape, it prevents the penetration of rodents, insects, and other small animals from the sewer into the house.
What gases are we talking about? In the sewer, there are gases such as methane and hydrogen sulfide, which are easily ignited. Other sewer gases can be poisonous and lead to suffocation, such as carbon monoxide.
That is why a separate P-trap is needed for the proper operation of each shower in the house.
What happens if there is no P-trap in my house?
The minimum harm that a broken trap or its absence can cause is a bad smell in your shower because dirt, debris, and other solid particles will not be captured by the shower drain trap.
It’s much worse if sewer gases get into your house. This can happen if the trap is not installed at all, or if the trap or the interceptor loses the water seal, it becomes a dry P-trap. This allows sewer gases to return to your home through the sewer.
How does a shower drain trap work?
A P-trap is installed in all houses under shower drains and sinks. This trap is an extremely important part of your home’s plumbing system. These are curved pipes, which always contain a small amount of water, which creates an airtight seal.
When water enters the P-trap, it pushes the old water into the next section down the drain pipes.
Read also about Bathtub gurgles when toilet is flushed. Why does your bathtub drain gurgle?
What does the trap consist of?
The inlet
The inlet is the place where the water enters the trap. In the bathroom, for example, the inlet is the shower drain.
The downward bent
The bend of the trap takes the shape of the letter U or the letter P if the inlet is included in this shape. This curved part holds enough water to ensure a tight seal between the sewer and the inlet to the P-trap. When new water enters the curved part, the old water is pushed out, going to the sewer.
In the middle of the U-shaped section of the P-trap, there is a cleaning hole, which is used to drain water from the trap during cleaning or repair.
The outlet
The outlet of the shower drain P-trap is located where the water enters the sewer line.
P-traps have various forms, which determine the name of this. For example, a P-trap and a U-trap are the same thing, but there is also an S-trap, which has the shape of the letter S in the horizontal plane. However, the principle of operation of different siphons does not differ.
The depth of the shower drain P-trap
There is no such thing as a standard trap depth. The depth of the P-trap is determined by the size of the pipes or fittings used. In any case, if your P-trap works well, you don’t need to worry about its depth.
How far should the P-trap be from the shower drain?
The maximum distance at which a P-trap and shower drain can be installed is 5 feet. However, the closer the P-trap will be located to the shower drain, the better. The best option would be if the P-trap is located directly under the shower drain.
Why is this so important? Because the farther the trap is from the shower drain, the higher the probability of unpleasant odors entering the house. Sometimes the reason may not be so much in sewer gases. How much is in the smell of decomposing dirt that is stuck in the area between the drain and the P-trap?
Dimensions of the shower drain P-trap
The minimum size of the P-trap for the shower drains is 2 inches. The same diameter has a pipe that is used to make a siphon.
For other drains, there will be a different P-trap size. For example, the size of the P-trap for the bathroom is 1 1/2 inches, and the size of the P-trap for the kitchen sink is 1½ inches.
How to clean the shower drain trap?
If you have noticed that the water does not go well into the shower drain, then perhaps the problem lies in the drain trap. You can clean the P-trap using simple household cleaning products that are available in every home.
Method 1. Baking soda and vinegar
This is the simplest, fastest, and easiest solution that you can take to clean the P-trap for the shower drain. Stock up on a small amount of baking soda, white distilled vinegar, and time.
- Pour 1/3 cup of baking soda into the shower drain, then add the same amount of white vinegar to it. You can also use apple cider vinegar, it won’t change anything.
- After you pour the vinegar into the shower drain, the vinegar will react chemically with soda and you will hear a characteristic hiss. This mixture can loosen any dirt in the drain and P-trap, as well as remove small blockages, hair, and soap foam.
- After 30 minutes, pour hot water into the shower drain to clean the pipes. You can clean your shower drain and P-trap in this way every few months.
Method 2. Drain cleaner
For quick and effective removal of any blockages, chemical sewage cleaners are most often used. However, it matters what this chemical consists of because by choosing the wrong cleaner, you can ruin sewer pipes.
The safest cleaners for P-traps are enzyme cleaners. There are also special products designed for main drainage lines.
Method 3. Use the cleanout
Some shower drain traps have a built-in cleaning function. This means that you have access to the P-traps at any time, you can open them and eliminate the blockage. To do this, you just need to unscrew the section, drain the water and eliminate the blockage.
To clean the P-trap under the kitchen sink, it will be enough for you to unscrew a few nuts, and then drain the water with garbage from the bowl.
If the P-trap is located under the shower or the bathtub, you will need access to the plumbing system of the house to be able to clean such P-traps.
You can also use a short auger or a plumber’s snake to push the blockage into the sewer.
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How to install a P-trap for the shower?
If you decide to install a new shower P-trap in your bathroom or replace the old one, then below you will find instructions on how to do this. If you install a P-trap yourself in a new bathroom, then try to install it as close as possible to the shower drain, and preferably directly under it.
- Cut out the shower floor under the drain. The size of this should be approximately 12 by 12 inches. Cut the floorboards and not too deep, so as not to damage the sewer.
- Free up the space around the drain. Now you will need a prybar to open the floor at the cutout point. You need to measure the length of the P-trap from one end of the U-shape to the other, and then you will use the same distance between the drain and the place where you cut the drain pipe.
- Connect the trap to the drain pipe. Using a connector and glue, connect the trap to the horizontal drain pipe.
- Reinstall the floor. Put the subfloor back in place, and then measure the distance from the P-trap to the subfloor. Cut a pipe of the same diameter as the end of the P-trap. Then reattach the shower drain. After the glue dries, that is, after about an hour, you will be able to use the shower as usual.
Alternatives to the P-traps for the shower
HepvO waterless valve
If you do not have a P-trap, and you need to install protection in any case, then the HepvO valve is an excellent alternative to the P-trap.
The HepvO valve can be installed horizontally, it is compact and great for installation under the drain hole, and you can keep it inside the frame of the building.
Bottle traps
Using alternatives to the P-trap, such as bottle traps, first, make sure that it is allowed by law in your place of residence because you will not be able to legally install a bottle trap everywhere.
Nevertheless, this is a pretty good alternative. The bottle trap has a horizontal sewage inlet with a lower half that is unscrewed to remove blockages and debris.
Grease traps
Grease trap separate water and fat. So grease does not get into the sewer and does not clog it. Before you think about installing such an alternative, make sure that you are acting legally.
Frequently Asked Questions
Where is the P-trap in a shower drain?
Usually, the shower P-traps are located under the shower drain. The trap can be located at a maximum distance of 5 feet from the shower drain. But the best option would be if the trap is located directly under the shower drain.
Is it possible to add bleach to the shower drain?
Yes, you can add bleach to the shower drain, but not for more than 15 minutes.
Conclusion
The P-trap is a necessary element in your home that can protect you both from the penetration of unpleasant odors and the ingress of garbage into your bathroom. In addition to U-trap and P-trap, there are also S-trap.
If you do not have a P-trap, then you can install an alternative: HepvO waterless valve, bottle trap, or grease trap. However, such an alternative must be legal in your country.
What is a shower P-trap?
The P-trap is part of the drain and sewer system of the whole house. The P-trap protects against sewer gases, garbage, or insects entering the house. P-trap is a pipe curved with the letter u, in the lower part of which there is always water, which creates an airtight seal.
How do you access the P-trap under the shower?
To access the P-trap under a shower, you will need to locate the access panel or remove the shower drain cover. Once you have located the access point, you should be able to see the P-trap.
When should I replace my P-trap?
A P-trap should be replaced if it is leaking, corroded, or clogged. Additionally, it is a good idea to replace a P-trap every few years as a preventative measure to ensure proper function and avoid potential leaks or blockages in the future. If you notice any unusual smells or slow draining in your sink, it may be a sign that your P-trap needs to be replaced.