The great thing about plumbing is that you immediately know when you have got it right without resorting to complicated testing equipment.

If a joint is not watertight when you turn the stopcock on, you get wet. Simple as that.

I once demonstrated this to my family when a fine arc of water came out of the toilet feed that I had just “fixed”, soaking the landing carpet.

But that’s the worst that can happen. Plumbing is safe to do yourself – as long as you have a mop handy. The worst part of it is ...