In the 1970s, our farm landlords built new cattle sheds on a greenfield site, and just tapped into the line supplying a farm cottage nearby, which is owned by them, but on our tenancy. Is this still legal ( if it ever was).
I’m just going from memory here but I think the industry act was introduced very early 90s so I’d imagine anything pre this would be exempt, unless of course it leaks and needs to be thrown dead in which case depending on if you did the repair work yourself you could struggle to get it livened up again.
But it could just be me but I wouldn’t be involving the water board or any insurance companys if I had a leak on my property, and I’m sure you wouldn’t be either!!