The seat of the standard toilet which was conceived by consulting engineer mahabir gill has been designed to slope at a downwards angle of 13 degrees so that the person who is sitting on it has.
Toilet on sloped floor.
When installing a floor drain on most indoor floor surfaces it is important to slope the floor slightly so that water will flow toward the drain efficiently.
Failure to achieve adequate slope will result in standing water problems.
Toilets are designed accordingly ie with level bases.
Place the carpenters level across the toilet bowl side to side and note where the bubble level is.
So if the floor is sloping you have to provide a level base to seat the toilet.
How to slope a floor for a drain.
Hammer a shim gently between the floor and the toilet base to bring a low side up.
This can be done with a mortar infill or some other material.
The shims should be inset 1 4 inch from the outside edge of the toilet.