Toilet testing company Maximum Performance has developed dummy poo made out of extruded soybean paste in order to assess how well a particular toilet's flush performs.

Soybean paste is used to create the synthesised faeces because it has similar physical properties such as density and moisture to human waste. The testers place extruded cylinders of the paste into toilet bowls along with toilet paper in order to test the performance of toilet flushes.


The original testing protocol used soybean paste that had been extruded through a 2.2 centimetre die and then cut into 10-centimetre-long 50g specimens. The size of the fake faeces being placed in the bowl is made progressively larger (in 50g increments) until the unit fails to clear the bowl in two or three flushes.

The minimum performance benchmark used by MaP was initially 250g of waste -- that is, a toilet unit should be able to completely evacuate 250g of waste in a single flush action. This value is based on a 1978 study from the medical journal Gut, entitled Variability of Colonic Function in Healthy Subjects. The study identified that 250g was the average maximum faecal size of the male participants in the study.

However, the US Environmental Protection Agency has adopted 350g of the soybean paste as the minimum performance threshold for "high efficiency" toilets.


Since the team started testing toilets in 2003, the average score of tested toilets has moved form around 350g to more than 675g.

The team has also developed an "encased specimen" -- where the soybean paste is enclosed in a thin latex membrane, much like how a sausage is made. This means that the test poo can be reused up to 100 times, making it easier and cheaper for toilet manufacturers to test their units at their own factories.

For more information about Maximum Performance's toilet tests, check out the company's website.