Companies like Cottonelle and Charmin heavily advertise their flushable wipes. They sound convenient, but plumbers make a lot of house calls that involve clogged toilets, backed up sewer lines, and flooded basements. Often the culprit is flushable wipes.

Consumer Reports checked out four flushable wipes from Cottonelle, Charmin, Scott and Equate. They all say they’re flushable and make claims like “sewer and septic safe” and “breaks up after flushing.”

In Consumer Reports’ standard tests, toilet paper breaks down quickly. But when testers ran the same test with the flushable wipes they didn’t break down at all.

Testers gave up after ten minutes. They even ran them for another ten minutes in a mixer, but the wipes still didn’t break apart.

After soaking overnight, two of the products, Cottonelle and Scott, did eventually break down. But even after 12 hours, the ones from Charmin and Equate stayed in one piece.

Consumer Reports testers say if you do decide to use these products, don’t flush them down the toilet.