How to Install a Flexible Drain Pipe

Installation, Benefits, and Disadvantages

Flexible drain part connecting PVC pipes next to water supply tubes

The Spruce / Kevin Norris

Flexible drain parts can be used to connect offset sink drains quickly. If you have ever been a little short on the pipe or had drain trap fittings that were just shy of the necessary length or angle, you'll appreciate the usefulness of flexible drain parts.

You can cut out the pipes under the sink and install a new sink drain using a 45- or 90-degree bend to make up the difference, but that may not be necessary for minor misalignment. If the pipes are very close to lining up and you do not have the time to completely re-do the drain system, then flexible drain connectors could be what you need. They are readily available and easy to get at a local hardware or home improvement store.

Here's how flexible drains work, their installation, and their adjustment.

Should You Use a Flexible Drain Pipe?

Smooth pipes are self-cleaning by the nature of their design. Flexible drain pipes are great in a pinch, but they have a few disadvantages you should consider. Due to their flexible, accordion-type walls, the grooves get grimy and clogs can build up over time. Also, DIYers may install them incorrectly, often leading to more leaks.

It's best to use flexible drain pipes when standard drain pipes can't fit a space properly—this is reserved for rare circumstances, such as retrofitting.


Flexible drain pipes are typically very affordable, and they make a great temporary solution to keep your drain functioning properly until a standard drain pipe can be installed.

Plumbing Codes

When using flexible drain parts, keep building and plumbing codes in mind. Just because you can flex these fittings into odd configurations doesn’t mean you should. Flexible fittings should be used to make up for a slight misalignment while still following the basic standards of drain system design. This means no uphill drains or funky loops.

How Flexible Drain Parts Function

Flexible drain parts can flex to one side or the other and from back to front or even extend to help make up the missing difference to make the drain trap or other drain parts line up. There are fittings for a bigger trap swing, couplings between two pipes that are not lined up, and flexible extension couplings for vertical or horizontal adjustments on one side of the pipe.

Finger pressing on side of flexible drain part

The Spruce / Kevin Norris


Installing flexible drain fittings is just as easy as installing any of the other tubular piping under the kitchen, bathroom, or laundry sink. They are held together with slip joint nuts and washers, making installing and removing them quick and easy. These flexible drain connectors are easily accessible if they have to be removed to clear a clog or to adjust the drain system below the sink, such as when adding a larger garbage disposal.

Slip joint nuts hand tightened after installing flexible drain part

The Spruce / Kevin Norris

Adjusting Flexible Drain Parts

Flexible drain traps are taller than most others, so it may be necessary to shorten the pipes above the continuous waste fitting to give the more extended trap room to flex over the span. Take your time installing flexible drain parts and play around with the many possible adjustments and positions until you find the one that is right for your installation.

When installing flexible drain fittings, the trap arm must not be tight to seal up correctly. The nut does not work well when overtightened, so it may be a good idea to try hand-tightening it at first and adjust from there if necessary. Run water and check for leaks when all drain fittings are connected and properly tightened. Make sure to test for leaks under the pressure of a large volume of water by filling the sink and then releasing the water to drain all at once.

Trap arm hand tightened with flexible drain part attached

The Spruce / Kevin Norris