Sooo

Q: Explain the spin of [water in] the toilets in relation to distance to the equator.

A: There is no relation. It's an urban myth. The water will spin whatever way the jets at the top are pointing.

There actually *is* an influence on the spin of water in the toilet bowl, the coriolis effect, which is a force that makes water spin clockwise in the southern hemisphere and counterclockwise in the northern hemisphere. The distance to the equator has no effect in itself, because coriolis forces are linear with the rotation speed (1/day=very slow) and the mass.

It's typically not observable in such tiny spots as it is overshadowed by other factors (the way the jets are pointing as you said) but there is an effect.