Repeated headlines about horrifying septic system disasters seem to indicate that “flushable” disposable wipes are in fact not flushable. For example, the 15-ton “fatberg” dislodged from a London sewer last fall was “caked in grease and fortified with wet wipes.”

These stories about costly sewage system clogs have multiplied as more disposable wipe products have hit the market in the past few years. Companies advertise their disposable wipes as “flushable” or “safe for sewer and septic systems,” but independent tests have found otherwise. A 2012 staff report by California’s Orange County Sanitation District noted that “field observations have found [flushable wipes] to be a cause of back-ups within the sewer system leading to sanitary sewer overflows, clogs at lift stations, and disruption within the treatment plant.” The report also summarized the results of the district’s flushability test: “After 24 hours the wipe remained intact and recognizable.”

Because the wipes do not disintegrate easily or quickly, they clog sewage treatment equipment and sometimes home septic systems as well. The National Association of Clean Water Agencies has reported the high costs associated with flushed wipes along with photographic evidence of wipe clogs.

In response to complaints about the wipes, Kimberly-Clark, the company behind brands like Cottonelle and Huggies, posted a video that purports to show how flushable wipes break down once flushed. Even in their own testing lab, which does not appear to simulate the grime and obstructions found in real-world sewage systems, the wipes began to disintegrate only after 35 minutes of constant agitation. Since the term “flushable” is not legally defined or regulated by the Federal Trade Commission, companies can still label these disposable wipes as such. While “flushable” wipes can technically be tossed into the toilet and flushed down, the “flushable” label as it is currently used fails to address the issues that arise once the wipe goes down the pipes.

A secondary problem with flushable wipes is that they are similar in function and appearance to wipe products that are specially designed to be disposed of in the trash rather than the toilet. Baby wipes or facial wipes, for example, are not even marketed as flushable and may contain logos or notices on the packaging that warn consumers not to flush. However, consumers who have heard of flushable wipes may simply assume that because non-flushable wipes look similar, they can be flushed. Both flushable and non-flushable wipes contribute to “fatberg”-like clogs.

Avoid flushing any type of wipe, “flushable” or otherwise, down the toilet. This will prevent costly clogs and environmentally damaging overflows at your local sewage system. In fact, it would be best to avoid disposable wipes completely since they produce waste that should end up in a landfill, and more sustainable alternatives (such as your normal dissolves-quickly-in-water toilet paper made of unbleached recycled paper) exist. But if you can’t let go of your wipes, make sure they are properly disposed of — in the trash.