About Flexible Drain Parts

A Guide to Installation

A flexible drain fitting
Aaron Stickley

Flexible drain parts can be used to quickly connect offset sink drains. If you have ever been a little short on 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. It is possible to cut out the pipes under the sink and install a new sink drain using a 45- or a 90-degree bend to make up the difference, but it may not be necessary for a 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 right for you. They are readily available and can usually be picked up at your local hardware or home improvement store.

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 difference that is missing to make the drain trap or other drain parts line up. I have seen fittings for a bigger trap swing, couplings to put between two pipes that are not lined up all the way, and flexible extension couplings for vertical or horizontal adjustments on one side of the pipe.

Installing Flexible Drain Parts

Installing flexible drain fittings is just as easy as installing any of the other tubular piping under the kitchen, bathroom and laundry sink. They are held together with the slip joint nuts and washers that make 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 make an adjustment to the drain system below the sink, such as when adding a larger garbage disposer.

In the example pictured here, I replaced a regular drain trap with a flexible drain trap fitting under a kitchen sink.

The old drain trap pipes were bent out of position which put a lot of stress on the fittings so they eventually developed a leak. It wasn't convenient to replace all of the drain pipes to make them all line up properly, so installing a flexible drain trap made sense. The flexible fitting made up the difference in aligning the pipes with the drain. The trap arm remained in the same place and I was able to use the flexible trap in the place of the old drain trap.

Adjusting Flexible Drain Parts

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

When installing flexible drain fittings, I found that the nut on the trap arm did not have to be very tight to seal up correctly. When it was overtightened, the nut did not work well, so it may be a good idea to try  hand tightening it at first and adjust from there if necessary.

When all of the drain fittings are connected together and properly tightened, run water and check for leaks. 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.

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 that you should. Flexible fittings should be used to make up a small misalignment while still following the basic standards of drain system design. This means no uphill drains or funky loops.