Why do American toilets clog?

After I moved here from Germany I noticed that Americans often have a plunger in their bathrooms. It took me not very long to find out that toilets clog more often in North America than they do in Europe. I didn’t learn about the reason why they clog, until I started ecoTransitions during the drought in 2007, supplying Australian designed Caroma Dual Flush toilets to Georgians. It’s a matter of design, trap way size and flush method.

Standard US toilets clear the bowl with siphon technology, so the waste in the bowl gets pulled into the drain and out into the trap way. In order to create this siphon action, the trap way needs to be as narrow as possible, usually around 2 to 2 3/4 inches.  You can see how siphon vs. washdown technology works here

Although most of the time this flushing method gets rid of the waste efficiently, there is a tendency for blockages to occur in the toilet trap way.

Australian and European designed toilets use a wash down method which “pushes” the waste down, instead of of “pulling” it. This is why European toilets have a larger diameter trap way which results in less clogging.

One drawback wash down toilets have versus siphon models is the smaller water spot in the bowl, which can result in “skid marks” happening on ocassion.  So it really comes down to a matter of  personal preference. If you are comfortable with getting out a plunger to unclog your toilet every now and again, then stick with an American style toilet. If you have issues with clogged toilets and don’t mind using a toilet brush every now and then an Australian or European style model may work better for you.