Those Accordion Pipes Under Your Kitchen Sink Need to Go

Open the cabinet under a kitchen sink and there’s a good chance I’ll find one: a stretchy, ribbed, accordion-looking pipe connecting the dishwasher drain to the rest of the plumbing. Someone probably used it because it bends to reach and it was easy to install. I get it. It’s still a bad idea.

The ridges catch gunk. Smooth pipe lets water and food bits slide right through. Ribbed pipe grabs grease, coffee grounds, and whatever else came off your plates, and it holds on. Over time you get slow drains, a funky smell from under the sink, and clogs that keep coming back no matter how much drain cleaner you pour in.

It sags. Drains need a steady downward slope, and flexible pipe doesn’t hold one. It dips in the middle, water sits in that low spot, and now you’ve got a little pool of old dishwater breeding smells.

It doesn’t last. The walls are thin and the material gets brittle. Cracks and loose connections happen, and a slow leak under a sink can go unnoticed for months. I’ve seen cabinet floors turn to mush and mold growing back there because of a drip nobody knew about.

One thing to clear up: the drain hose coming off the back of your dishwasher is ribbed, and that’s normal. I’m talking about the pipes after it, in the plumbing under the sink, which should be smooth-wall.

The fix is usually simple. A smooth-wall trap and fittings run about $30 at a hardware store, and it’s an easy swap for a handy homeowner or a quick job for a plumber.

While you’re under there, check that the dishwasher hose loops up high under the counter before it connects to the drain. That loop keeps dirty sink water from backing up into your dishwasher. It’s another thing I see missing all the time.

If you’re buying and this shows up in my report, don’t panic. It’s a small fix, not a dealbreaker, but it’s good to know about. And if you’re selling, swapping it out before you list is an easy way to avoid one more item on the buyer’s report.