Hi Sally,
It depends on where abouts in the country you are if you live in a hard water area then yes deffo. But then not worth it if your lucky enough to have soft water in your area i have Yorkshire Water which comes of the moors nice and naturally filterd & very soft. no lime scale in my kettle. wooohooo...
Lucky you gasman!!! We`re on the edge of chalk land and our water is about as hard as it gets....so, yes, go ahead BUT make sure that you keep the kitchen tap as HARD water. Naturally soft water is fine, but water treated to be soft should not really be used for drinking and cooking.
We are on the edge of the chilterns. It is worth every penny as it saves wear and tear on appliances, I use significantly less chemicals to clean than neighbours, house does not look so grubby either. The savings on cleaning products, soaps, shampoos etc soon make up for the initial costs.