Conventional toilets create a water spot in the toilet bowl at the end of each flushing, by using a refill valve that dispenses some water to the toilet bowl. In a water saver toilet, care must be taken in its design to assure a water spot of sufficient size.
It is possible to save water when flushing only urine by using perhaps 1.5 liters instead of 3 liters in a water saver toilet flushing. However, when less water is flushed, less water may be available to create a water spot. A toilet that enabled a good flushing with only about 1.5 liters of water, and that provided a sufficiently large toilet bowl spot would be of value.