P-trap Doesn’t Line up with Drain, How Can I Fix It

A bathroom remodeling project isn’t complete without installing a new sink. While it adds functionality to a bathroom, a few factors can quickly limit its effectiveness. One such scenario is when the p-trap doesn’t line up with the drain.

It creates an awkward appearance, and noxious sewer gasses seep through, causing your bathroom to stink. However, you can realign the p-trap to the correct position with a few DIY hacks. We look at some of them.

In A Nutshell

When p-trap doesn’t line up with drain, or the bathroom sink drain pipe and p-trap don’t meet, you can adjust the pipe’s length horizontally, vertically, or install a pipe extension on the drain pipe and the p-trap to align them correctly.

The Basics of a Sink Drain Installation

Typically, conventional sinks have three components — the p-trap, tailpiece, and extension pipe. A p-trap derives its name from its shape, which consists of a looping configuration that takes on the letter P. 

It has a bend that holds a small amount of standing water every time the sink is used. The water acts as a seal to the drain opening, preventing gasses from rising from the sewer system to the bathroom.

The p-trap also acts as a resting point for valuable items that get drained down a sink. The objects remain trapped instead of getting washed into the main drain. Another benefit of the p-trap is that it’s an excellent place to clear clogs from the branch drain leading into the wall or the trap bend.

In a typical drain trap assembly, the p-trap and the extension pipes are lined between the main drain outlet and the p-trap, while the tailpiece pipe runs between the p-trap and the sink.

A drain trap assembly may be sold as a kit which consists of the trap arm and the trap bend. 

Some kits have a tailpiece extension extending from the tailpiece connected at the bottom of the sink. For double-basin sink setups, the basins have separate tailpieces joined before entering a shared p-trap. When installing a vanity, the sink drain must align to the main drain’s inlet and the outlet (strainer) to complete the path from the faucet to the sewer.

Since the distance between the components varies from one sink to another, drain assembly components are designed to ease modification and adjustment. Therefore, if the p-trap doesn’t align with the drain, adjusting the length and height of the drainpipes goes a long way in fixing the problem.

Reasons a P-trap Doesn’t Line up with Drain

Three main reasons cause the p-trap and the drain to not align. 

Wrong Installation of the P-trap and the Sink Drain Pipe

Improper placement of the p-trap and the drain pipe can lead to a misalignment between the pipes. For example, you may have assembled the wrong parts during installation or aligned them incorrectly, causing the p-trap not to line up with the sink drain.

The p-trap may have been placed higher from the sink drain causing water to use more force when flowing. It could also be that the p-trap has been placed under the main exit drain preventing gravity from taking its course. Measuring the p-trap height ensures proper placement and installation.

Using the Wrong Size of the P-trap and the Drain Pipe

The drain pipe and the p-trap must have similar sizes to align correctly. A drain pipe has a standard diameter of 1-1/4 inches, but some sink drain holes can accommodate pipes as large as 1-1/2 inches and 1-5/8 inches. Therefore, it’s essential to check the size of the drain hole before buying and installing the p-trap.

Sizing also applies to the distance between the sink drain and the p-trap. A good rule of thumb is to keep a distance of 24 inches between the pipes; if it exceeds this length, you’ll have difficulty installing and aligning them. Most DIYers rely on the previous measurements without checking the new bathroom setup.

P-trap Installed Far from the Drainage Space

This problem is common in older bathrooms where the sink is installed far away from the drainage system. The long distance makes it difficult for water to flow from one point to another and increases the chances of creating a leaky drain sink and p-trap connection.

Leaks not only create a safety hazard, but they also damage recently installed parts. Besides maintaining a 24-inch distance between the sink drain and the p-trap, you must ensure the slope of the trap arm is ¼ inches for every foot distance.

What Do You Do When P-trap Doesn’t Line up with the Drain?

You don’t need to hire a pro to fix the problem. Simple DIY hacks should get the p-trap lined with the drain and functioning effectively. Here are four ways to fix the problem:

  1. Get the right size of the p-trap
  2. Adjust its horizontal orientation
  3. Adjust its vertical orientation
  4. Replace the drain trap

1. Get the Right Size of the P-trap

To do this, you will need a pipe wrench and a flexible drain pipe. 

The most common reason a p-trap doesn’t line up with drain is using the wrong size. You need to remove the p-trap and inspect its size to ensure you’re using the right one. It would help if you had a pipe wrench to twist the collar of the p-trap until it comes loose. 

Then, check if the diameter is within the standard threshold (1-1/4 inches) and buy the right one from the hardware store if you picked the wrong size.

2. Adjust the P-trap’s Horizontal Orientation

You could be using the right size of the p-trap, but if it doesn’t align with the drain, there may be a problem with the installation. The solution is to readjust the drain pipe horizontally or vertically. 

Then, select the right length and height of the p-trap when connecting it to the drain pipe and join the right end. Typically, p-traps have two curved pipes — a trap arm and a trap bend.

The trap arm has a curved end that fits into the trap bend and a straight one connecting to the drain outlet in the wall. When adjusting the trap’s horizontal orientation, you must loosen the connecting nut and twist the lower part of the p-trap to align the extension pipe with the main drain outlet. 

If turning the trap doesn’t line up the p-trap with the drain, try connecting a flexible drain extension as in the third step. Once adjusted to the right height and length, lock the p-trap collar and secure it against the drain sink.

3. Adjust the Vertical Orientation

This method comes in handy if the extension pipe connecting the drain pipe and the p-trap is higher or lower than the drain inlet. The simplest way of adjusting a drain assembly’s vertical orientation is to increase or reduce the tailpiece length.

If raising the pipe’s vertical position, reduce the length of the tailpiece by cutting it. However, if you want to reduce its vertical position, add tailpiece extensions to increase its length.

4. Add an Extension Drain Pipe

By now, the p-trap should line up with the drain pipe. If not, add a flexible drain pipe. Be sure to get the right size by checking the length of the trap, drain sink hole size, and cap measurement. Then use the tube to connect the drain pipe and the p-trap. 

If the pipe is too long, cut it across the circumference to ensure it sits flush within adjacent components. Here’s how to add an extension drain pipe:

  • Connect the collar and end of the flexible extension to the existing tailpiece. Then tighten the collar with a pipe wrench and avoid over-tightening it.
  • Bend the flexible tailpiece and join it to the p-trap. Insert one end to the p-trap opening and tighten the locking collar.
  • Then fasten the drain plug and run water to see if the p-trap and drain pipe align properly. Open the drain plug and allow water to drain out as you check for leaks. Then tighten the locking collar to eliminate any leakages.

5. Replace the Drain Trap/P-trap

Sometimes the best way to solve the problem is to replace the p-trap with a new one. It might be worn out or too damaged to repair. You can purchase a new drain assembly, often sold as a kit that consists of the trap bend, trap arm, and a straight end that joins the main drain to replace the old p-trap. Here’s how to do it:

What you need:

  • A bucket
  • Pliers
  • Pipe cutter/ hacksaw
  • New p-trap kit

1. Remove the Trap Bend

First, remove the old trap bend by loosening the slip nut on both ends of the bend. You can turn them by hand, pipe wrench, or pliers. Then detach the trap from the tailpiece and empty any contents in a bucket. Also, remove the nuts from the end of the tailpiece and any extension pipe used to connect the trap bend and the sink tailpiece

2. Remove the Trap Arm

Loosen the screws securing the trap arm to the drain pipe and pull it out. If it’s stuck, twist it back and forth while pulling.

3. Test the New P-trap

Fit the new p-trap and check if it lines up with the drain. You may need to cut the trap arm using a pipe cutter to ensure it has the same length as the old trap arm. Check the tailpiece too to find out if it needs to be cut to a suitable length.

4. Fit the Parts

Connect the trap arm to the main drain pipe and to one end of the trap arm to create a continuous loop. Slide in the nuts against the fittings and fit them onto the threaded hubs. Then adjust the trap bend and arm to ensure they line up. Ensure the trap arm has a slight slope (1/4-inch per foot) towards the wall, then screws.

5. Test the New P-trap                                                    

Open the tap and allow water to run down the drain while checking for leaks. If leaks are at the joints, tighten the nuts with pliers. Avoid overdoing it, especially if using plastic nuts because they’re prone to breaking.

So, What Do You Do if P-trap Doesn’t Line up with Drain?

You don’t have to engage a professional when the p-trap doesn’t line up with the drain. Instead, you can fix the problem with a few home tools and DIY tricks. First, check the sizes of the p-trap and the drain to ensure they match. If the p-trap is larger than the drain pipe, get the right size (usually 1-1/4 inches).

Some drain pipes can connect to p-traps as large as 1-1/2 inches and 1-5/8 inches, so you want to verify their sizes accurately. If the size isn’t the problem, adjust its orientation horizontally or vertically or add an extension pipe. Alternatively, replace the p-trap with a new one.

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