I have just bought a set of Ikea kitchen taps which have a 'rincer'. Looking inside the box, they include a pair of "non return" valves.
Do these have to be fitted? None of my current taps have non-return valves fitted and I wonder if they now need to be fitted due to a change in the 'building regs' ?
Are they optional? Do I have to fit them? If not, what the benifits of fitting them (or the implications of not)??
Jon