Do all showers need AP trap?

Author: Leola Jones  |  Last update: Friday, June 27, 2025

Rules and Regulations to Know Regarding Shower Traps As we previously mentioned, it is a law in the United States that every shower has a P-trap.

Is an AP trap necessary for a shower drain?

Do shower drains have P-traps? Unless you're a professional plumber, you might not know what a P-trap is or what purpose it serves. The truth is, the P-trap is an integral part of your shower's drain.

What happens if there is no P-trap?

However, if there were no P-traps in the plumbing system, these gases would be constantly vented out through all of your drains instead. This would result not only in nasty odors wafting up from your drains, but could also lead to health issues as some sewer gases are harmful.

What is the alternative to the P-trap?

Water remaining in the bend of the trap seals off the pipe, blocking the gases from entering the room. Sanitary waste valves (SWV) offer a compelling alternative to traditional p-traps for sporadically used locations such as vacation homes, guest bathrooms, dorms, stadiums, and seasonal facilities.

Is a P-trap necessary?

Even if you aren't into plumbing, you may have seen the U-shaped piece under your bathroom or kitchen sink. This plumbing tool, P-trap, is an essential part of your home's plumbing system. It can be made from PVC pipe or steel; the latter is always used for exposed plumbing as it is more attractive.

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What are the disadvantages of P-traps?

Disadvantages of P-Traps

One common issue is that the water seal can be protected if properly maintained or if there are blockages in the drainpipe. This can lead to the escape of sewer gases and unpleasant odors. The trap is regularly inspected and cleaned to ensure its proper functioning.

Where are p-traps required?

Compliance with plumbing codes: P-traps are required where an open drain line discharges wastewater into a drain waste-vent system. Prevention of blockages: P-traps help trap solids that might otherwise clog the drain or sewer line.

Can I use an S-trap instead of AP trap?

We can use a trap to catch any water or other fluids not meant to be in the basin or the drain. P-traps are typically used in kitchens as they can handle cold water. In contrast, S-traps are more suited for bathrooms because they can only handle warm water.

Do all drains have P-traps?

Your plumbing system, however, is a two-way street. A specialized fitting called a p-trap creates a powerful barrier that stops sewer gas and odor from entering your home. The trap is employed in any plumbing system that uses a drain and accepts sanitary waste from tubs, showers and sinks.

Can you use bottle trap instead of P-trap?

The suitability of a bottle trap or a P trap can also depend on the specific fixtures you're working with. For pedestal sinks or wall-mounted basins where plumbing is visible, a bottle trap may be more appropriate.

Do you need a P-trap under a bathtub?

All of your showers, bathtubs and your washing machine also have P-traps down underneath the drain. The P-trap underneath your sink can easily be removed simply by loosening up the fittings at each end. This comes in handy in case you accidentally drop your wedding ring or anything else down the drain.

How to unclog a sink with no P-trap?

Pour one cup of fresh baking soda down the drain, followed by one cup of white vinegar. Place a rubber stopper or other sink hole cover over the drain opening. Wait 15 minutes to allow the vinegar and baking soda to unclog your drain, Then take out the drain cover and run hot tap water down the drain to clear the clog.

Does every plumbing fixture need a trap?

Every single fixture in a plumbing system has some sort of P-trap. And even though there's a certain artistry to its curvy shape, it's not just an adornment. It performs a special function for the fixture it's connected to or 'serving'.

Can a shower drain have a 90 degree elbow?

Yes, you can use a 90-degree elbow in a shower drain to redirect the plumbing.

Why does my shower drain smell like sewer?

If your shower drain smells like a sewer, then this is a sign that your P-trap may not be doing its job of blocking sewer gases from escaping into your bathroom. If you're dealing with a mustier or general odor, then your P-trap could still be the problem, but in this case, it likely needs to be cleaned.

Do you need a shower trap?

A shower trap is a crucial component of a shower's drainage system. It is located beneath the shower tray and is designed to support the efficient flow of water.

Do showers require AP traps?

The P-trap has the important job of preventing sewer gasses from making their way into your bathroom. Although you can't really see the shower trap, it is a super important part of your plumbing system. Does a shower drain need a trap? In short, yes, every shower drain in the United States must have a trap or P-trap.

What can I use instead of a P-trap?

Waterless traps

Wavin Osma's HepvO waterless trap provides a hygienic alternative to the traditional trap because it cannot dry out. Its self-sealing membrane provides permanent, watertight protection.

Are P-traps necessary?

The “P” trap (named after its shape, has nothing to do with urine) is there to prevent sewer gases from entering your home. It stays filled with water to form a barier. You need it. Sewer gases are not good for you.

Why is S-trap illegal?

The “S” trap is prohibited under the Uniform Plumbing Code throughout the United States. This is because the “S” trap will siphon or suck water out from the trap which will end up releasing methane (sewer) gases into the home. So, it is a code violation and if you are doing remodeling, you will have to replace it.

Which is better, a P-trap or a S-trap?

However, when comparing a toilet P-trap and S-trap, P-traps feature a modern design, reduce siphoning risks, and meet updated plumbing codes. S-traps are less expensive and fit older plumbing systems, but they're more likely to allow toilet gases to escape and may not meet modern plumbing codes.

Can AP trap be installed incorrectly?

In some cases, an improperly installed p-trap can also lead to clogs. The p-trap is designed to trap debris and prevent it from entering your plumbing system, but if it's not installed correctly, debris can build up and cause a blockage.

Do all drains need an AP trap?

P-traps are necessary for drainage systems where there might be sewer gasses that are trapped inside your trench drains. These are commonly necessary for sewer drains but might also be used in other drainage systems that could be exposed to gasses that cause foul smells.

What is code for P-traps?

Each “P” trap shall have a water seal of not less than 2 inches and not more than 4 inches and shall be set true to its seal. (6) Size. Traps shall be not less than 1 1/4 inches in diameter. A trap shall not be larger than the waste pipe to which it is connected.

Can I use a 1.5 inch pipe for a shower drain?

When it comes to installing drains, size matters. The recommended pipe size for a shower drain is 2 inches, whereas most tubs use 1.5-inch pipes. Why the difference? Shower pans are shallower than tubs, so there's a higher risk for overflow.

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