What Is a P-Trap?

A P-trap is a curved section of pipe beneath sinks, tubs, and other plumbing fixtures. Its distinctive U- or P-shape works to catch debris before it makes its way further into your plumbing, keeping your system sanitary and safe.

Keep reading to learn more about what a P-trap does, how to clean a P-trap, and how to remove an object that gets stuck in one.

What Does a P-Trap Do?

The purpose of a P-trap is simple but crucial: it holds a small amount of water in the bend to create a seal that blocks odors and sewer gases from bubbling up through the drain. Without this water barrier, your fixtures could smell like a sewer.

As a bonus, the P-trap catches any item that may cause a clog before it becomes a serious problem. It can also help when an item is accidentally dropped down the drain. Clogs from debris are one of the most common reasons toilets break, and a P-trap is a great way to stop these clogs from moving further into your system.

Where Are P-Traps Found in Your Home?

P-traps are commonly found under:

• Bathroom sinks
• Kitchen sinks
• Bathtubs and showers
• Laundry tubs
• Floor drains

Do Toilets Have P-Traps?

Technically, no — toilets do not have P-traps in the traditional pipe sense. Instead, they’re built with an internal toilet trapway. This is a curved passage inside the toilet that traps water to block sewer gases.

This built-in toilet trap can also come in handy, especially if you’ve dropped a toy or flushed keys down the toilet. If you’re lucky, the foreign object will get lodged in the S-curve of the trap in the toilet, allowing you to get it out before it moves further down your plumbing.

Over time, if you notice more frequent clogs or cracks in the toilet trapway, it could be a sign that you need to replace your toilet.

How Does a P-Trap Work?

A P-trap works by maintaining a barrier of water inside its curve. Here’s how it functions, step by step:

1. Water from the fixture flows into the trap.
2. The bend in the trap retains a small amount of water.
3. This water forms an airtight seal that blocks sewer gases from traveling back up the pipe.
4. As more water flows through, old water in the trap is pushed out and replaced, maintaining the seal.

The trap also catches small debris, preventing it from traveling deeper into your plumbing system.

What Happens If a P-Trap Fails?

If your P-trap isn’t working, it can cause noticeable problems like:

• Sewer smells coming from the drain
• Gurgling sounds as water flows through
• Slow drainage in sinks or tubs

These issues often stem from dry traps (common in unused drains), blockages, or cracked seals.

How to Clean a P-Trap

Cleaning a P-trap is usually a simple DIY task. Here’s how to do it:

1. Place a bucket under the trap to catch water or debris.
2. Unscrew the slip nuts holding the trap in place.
3. Remove the trap and dump out any gunk.
4. Clean the inside with a bottle brush or wire.
5. Reattach the trap and tighten the nuts by hand.

If your P-trap is metal or showing signs of corrosion, you may want to call a plumber. The same goes for deeper blockages or leaks. This could be a sign you need floor drain maintenance.

Can Items Get Stuck in a P-Trap?

Yes, it’s common for items to get stuck in a P-trap, such as:

• Rings or jewelry
• Hair ties
• Cotton swabs
• Toothpaste caps

If you drop something valuable into a sink, use the above steps for cleaning a P-trap to try and retrieve it. Things are a little harder if you drop something down a toilet. Here’s how to remove an object from a toilet trap:

• Use a plunger to try bringing the object back toward the bowl — this is one of the best eco-friendly ways to unblock a toilet.
• Try a toilet auger (closet auger) to reach and hook the item.
• Use a wet/dry vacuum (if safe and appropriate) to suck out the object.
• Remove the toilet as a last resort if the object is still lodged deep in the trap.

When to Replace or Repair a P-Trap

Watch for these signs that your P-trap needs replacing:

• Visible corrosion or rust (on metal traps)
• Persistent leaks or dripping water
• Strong odors despite cleaning

If you're replacing a P-trap, here are the most common materials and who they're best for:

• PVC traps: Lightweight and affordable, these are great for DIYers and homeowners who want an easy-to-install option.
• ABS plastic traps: If you need extra durability and live in colder climates where expansion and contraction are more likely, ABS is better.
• Chrome-plated brass traps: These are best for homeowners who value appearance or need a professional finish.
• Cast iron or galvanized steel traps: These are mostly used in older homes to match existing materials.

Use a P-Trap to Keep Sewer Gas Where It Belongs

P-traps play a huge role in protecting you from odors, gases, and lost valuables. If you suspect a leak or clog in your P-trap — or your toilet trapway isn’t doing its job — Roto-Rooter can help with expert diagnosis, cleaning, or replacement.

Schedule your P-trap inspection today to keep your drains in top shape.