Toilets until recently have relied upon an enclosed rim around the top of the bowl to direct flush water around the bowl. The majority have used box rims where the water is channeled through a box section and a series of punched holes on the underside allow water to escape into and clean the bowl equally around the perimeter.
A Rimless toilet, as the name suggests, does not have an enclosed rim. Instead, the flow of water is directed around the perimeter as it enters the bowl when flushed.
A properly engineered Rimless toilet will flush equally as well as a conventional rimmed toilet.
Independent tests have established that Rimless toilets are significantly more hygienic than standard toilets, but whether the scientific claims are accurate or not, common sense would suggest that the much simpler design of Rimless toilets provide fewer opportunities for the build up of bacteria and for limescale to lurk un-noticed.
There are some claims that Rimless toilets use less water, but since flush volume is determined by the amount of water released by the cistern, any difference will be negligible.
While less limescale and bacterial build up is more attractive, not every Rimless toilet looks particularly attractive. Exposed holes directing the flow of water and ledges around the inside of the bowl can look quite peculiar and you should ensure that you know what the inside of the bowl looks like before purchasing.
The VitrA Rim-ex toilets that are used to illustrate this feature are some of the best engineered, aesthetically pleasing and well thought through designs. The specially engineered water diverter located at the back of the bowl can be removed for cleaning.
Rimless toilets provide additional benefits without any compromise on standard toilet features or performance and it is likely that they will become the standard rather than an option.