Quantum objects, such as atomic nuclei, have properties of both waves and particles. Quantum effects aren’t usually manifest to the naked eye, but in this case they may be responsible for some of water’s unusual features. “The quantum effect in water is abundantly obvious,” says Alan Soper of the Rutherford Appleton Laboratory in Didcot, England.
So if anyone wants to know where QM can be applied to, point to them the stuff flowing out of their taps.
I'll find the actual paper that this was published and put the reference here.