Improper Application of Plumbing Materials and Why It’s a Problem

‍One of my home inspectors here at HomePro Inspections recently discovered an example of improper plumbing materials used under a home's sink during an inspection. This is another case of DIY gone wrong, highlighting potential future problems.

Improper flexible plumbing under a kitchen sink

‍The white corrugated flexible pipes in your photo are not an appropriate substitute for a P-trap. Although they bend into a “U” shape, they don’t work the same way a real P-trap does.

Here’s why:

A P-trap must hold a water seal

A proper trap, such as a standard PVC or ABS P-trap, is designed to hold a small amount of water permanently. That water creates a seal that prevents sewer gases from entering the house.

Corrugated tubing traps debris

The ridges inside those hoses create many places where grease, food particles, and soap residue can collect. This causes frequent clogs and slow drainage. Smooth trap pipes are designed to prevent buildup.

It doesn’t meet plumbing code

Most plumbing codes (like IPC and UPC) require a properly sized, smooth-wall P-trap, correct trap arm length, and rigid connections.

Flexible accordion-style drain tubing like this is usually not approved for permanent installations.

They can sag and form multiple traps.

While this setup keeps water in place, it can become completely full. This configuration may stretch, shift, and sag over time. Flexible hoses tend to droop, which can accidentally create multiple low spots (double traps). This can lead to slow drainage, air locks, and gurgling when draining the sink.

Summary

These hoses are usually meant for temporary or emergency use only, not for long-term plumbing. Solving this type of problem with solid, smooth-bore piping is the proper solution.

At HomePro Inspections, we are trained to identify these issues during home inspections. Any problems are documented and recommended for resolution by a qualified professional.

 Visit our website to learn more or to schedule your home inspection in the Rochester, Owatonna, and Faribault, MN areas. You can contact us today at (507) 202-8942, email us, or use our online “Schedule Now” feature to schedule an appointment.