Ring your water company, they will talk you through it. I do it through a third party because it's cheaper, the water board even pointed me towards them. They deliver and pick up everything then just bill you, or......
You could just get one off eBay and not get caught.
I think it's maybe a £5000 fine, more if you break a fire hydrant, more if you break a fire hydrant and then there is a fire and no water for the fire service.