How do you tell if a drain has a trap?

Author: Kamille Mitchell  |  Last update: Friday, February 6, 2026

You can check by inserting a snake into the shower's drain. If you hit water soon after entering the drain, you most likely have a P-trap. It may also be visible with a flashlight, depending on the shower's design. If you do not have one, you'll want to leave the installation to a qualified plumber.

What does a drain trap look like?

A P-trap is also known as a sink trap. It's the strongly curved portion of piping under the sink. It's called a P-trap because the bend makes it look similar to the letter P turned on its side. It also looks like a U or a J when it's not on its side.

Do all drains have traps?

There are traps in every drain because any connection that leads to the drain system is also a possible outlet for sewer gas. Even your toilet has an internal trap shape to its porcelain configuration that serves exactly the same function.

How to find a drain trap?

The easiest way to find the sewer trap is to locate the fresh air inlet pipe which is typically located near the front wall of your house. The fresh air inlet outlet is also on the outside front or the side of your home, and it will be exposed and covered by a grating.

Where is the drain trap located?

You will find them under sinks, wash tubs, showers, bathtubs, the toilet has it's own trap designed right in so unless you want your house to smell like fermenting poop, food and the like you need them.

How Do P-Traps Work? 5 Drain Issues to Watch Out For

Does a main sewer line have a trap?

If your house was constructed prior to 1989, there's a strong likelihood that it contains a house trap or sewer trap, a plumbing device used to 'trap' gases in the sewer system so that they do not seep out into the home's interior. Today, these devices are obsolete.

How do I find out where my drains are?

You generally have two options when it comes to finding the drainage system beneath your property. You can reach out to your local council and ask them to send you your drainage plan. The other option is to contact your local drainage experts and ask them to map your drains.

How to tell if a drain has a trap?

You can check by inserting a snake into the shower's drain. If you hit water soon after entering the drain, you most likely have a P-trap.

How to find out where a drain is clogged?

You can drain the pipe, fill the partially blocked pipe with hot water, and use your forearm to feel the pipe. Alternatively, instead of using your forearm, you can opt for other tools like an infrared camera or a temperature gun if you're in a position to get one.

How do you remove a drain trap?

To remove the drain trap, unscrew the slip nuts with a wrench and slide them out of the way. Directly beneath the drain outlet of every kitchen sink and every bathroom lavatory is a trap. This element is vital not only to the proper functioning of the drainage system but also to your health and safety.

Does my floor drain have a trap?

You see, floor drains have one of those U-shaped P-trap pipes just like your bathroom sink drain. That U-shaped pipe is designed to hold water, which stands in the pipe and prevents sewer gases from coming up through the drain. If you smell sewer gas, grab a bucket of water and start pouring it into the floor drain.

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'.

What is the most common type of trap in plumbing?

P-Trap. The P-trap is the most common house plumbing trap. Its U-shaped design holds water and is installed beneath sinks in both bathrooms and kitchens.

Does my sink have a trap?

The trap typically sits underneath the basin vessel. This is because sinks are designed to drain water downwards and out of the vessel, into the trap. Depending on the design of your basin, you may or may not be able to see your basin trap.

How much does it cost to replace PVC pipe under a sink?

They cost around $0.50 – $5 per foot. So, you can expect the cost of the replacement to be well within the average range if you choose PVC. Copper pipes cost around $2 – $10 per foot. If you have cast iron drain pipes, you can expect to pay up to $10 – $20 per foot of pipe.

How do plumbers clear blocked drains?

In many cases, professional drain cleaning tools like a toilet auger or hydro jetting equipment will be enough to deal with a deep clogged pipe. However, if there is damage present, you may need additional repairs or pipe replacement services.

How to tell if an outside drain is blocked?

This blog will point out the key signs to look out for before discussing the steps to take when you think your drainage system is clogged.
  1. Slow Drainage. ...
  2. Unpleasant Smells and Odours. ...
  3. Gurgling Sounds Coming from Drains and Plug Holes. ...
  4. Raised Water Levels.

When I flush the toilet water comes up in the shower drain?

When you notice toilet water backing up in shower drains, it could indicate a problem somewhere in that smaller network of the overall sewer line. As such, professionals should inspect your system when you notice sewage coming out of your shower drain to identify the source.

How do I know which drain is clogged?

If only one sink is slow, the blockage is probably relatively close to the surface. You may be able to clear it yourself without too much difficulty. However, if multiple sinks start draining slowly all at once, the blockage is probably somewhere in the sewer line, which is more difficult to reach.

How do I know if my underground drain is clogged?

If you notice water gushing back out from the drain pipe or leaking out from the seams on the adapter, that is a sign that there are clogs in your underground drain.

How do I find where my drain goes?

To find the drains on your property, consult with your local council to search for the drainage plans for your property based on the age of your property. A CCTV drain survey can also map and record the drainage system on your property if you are unable to find property deeds.

How do I find a clogged main drain?

The following are signs to watch for that can help you detect a sewer blockage in your home.
  1. Multiple Fixtures Are Clogged. ...
  2. Flushing the Toilet Causes Water to Come Up Elsewhere. ...
  3. Water Draining From Your Washing Machine Causes an Overflow in Other Locations. ...
  4. Drainage at the Cleanout. ...
  5. Slow-Draining Sinks or Toilets.

Does every house have a drain cover?

A sewerage manhole cover is found along the line of where the sewer or drain runs. This is the same for public sewers and private drains. Not every property will have a manhole on their property, for example if you share a sewer it may be on a neighbouring property.

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