Will the toilet drain leak if it is 5 cm shorter?

After a long time, it is very likely to leak, so if you want to find a way to make up for it, you can use waterproof paint to paint the cement surface between the drainage pipe and the floor tiles many times until a waterproof membrane with a certain thickness of rock is formed and then install the toilet, so that you can avoid or reduce leakage.

After a long time, it is very likely to leak, so if you want to make up for it, you can use waterproof paint to paint the cement surface between the drainage pipe and the floor tile several times until a certain thickness of waterproof membrane is formed before installing the toilet, so as to avoid or reduce leakage. If there is a sealing ring between the toilet bowl and the sewer pipe, you must remember to put the sealing ring, which can be sealed with the sealing ring. If you don't have a seal, sooner or later it will seep water from the side.

Refer to it yourself and solve it according to the method, so as not to be troublesome to repair after the water leak

It depends on the situation, if it is more than the original ground, just make the surrounding waterproof, if it is lower than the original ground, then you have to take over.