Do I need a non return valve?

[gholland]

I am about to replace the sink in my bathroom. The new sink has a mixer tap, which is supplied by secondary cold water (from the loft tank), and hot water from out hot water cylinder.
Will either supply pipe require a non-return valve ?

[rosebery]

No because there is no danger of syphonage there being an "air gap" between the tap spout andd any water in the basin.

If it was a BSM and the shower hose could fall into the water that would be a different matter.

Cheers