When buying a new toilet, not an easy task.

Replacing an old toilet or installing a low-flow or a high efficiency toilet after a renovation will not always work as planned and could be different reasons why the new models can plug more often or required double or more flushes.

We have to remember that the new toilets models are all tested on modern plumbing, usually pipes with less diameter than the older 4” to 6 inches cast iron pipes we still found in many renovations. After the toilet is flushed will be little water at the bottom of a 6 inches pipe to move waste along, that's maybe one of the main reasons why low-flush toilets work better in new built homes.

From the plumbing point of view and design is always a good idea to have toilets in a position where other plumbing fixtures ( showers, sinks .. ) will contribute to wash down the drain pipes with their black water.

That's also the reason why others toilets in the house tend to plug more often than the master bathroom's toilet where there is a shower washing the drain down.

Options in what type of toilet to buy are as diverse as companies who manufacture them, in north America ( USA and Canada ) MAP ( Maximum Performance ) is an online database with results and evaluations about some 2800 tested toilets and a good reference guide when in need of some info to decide what type of toilet is best for your home.