Even though the water in toilets spins different directions in the northern and southern hemispheres, it is not a result of the Coriolis effect. To see the effect, one needs a much bigger scale, such as hurricanes. The reason water rotates different directions in northern and southern hemispheres when flushing, is the different direction of the jets. The Coriolis effect does exist, but it is too small to see on such a small scale.