I don’t live in Malham but my mum used to years ago (I’m talking 1960s here) and she says that the water was incredibly hard. She once played host to a student teacher from Ghana who was horrified to find that her skin turned grey when she tried to have a bath because of the calcium suspended in the water.
But, like I said, that was 50 years ago or more, they were probably getting water from a bore hole – whether things have changed since then or not I don’t know. Having said that, I work in Skipton and the water here seems soft enough, it brews a cup of tea nicely.