Kat, the water will be disconnected so that the kitchen and bathroom can be demolished. That just happens to be the only bit of the house with plumbing, apart from the outbuilding in the garden (which has a loo and vanity basin) and an outdoor tap which just happens to be on the kitchen wall.
Plan A is to try and keep the water supply to the outbuilding, which may or may not be possible, and hopefully set up a supply in the yard (the builders are going to need a water supply). Plan B is me going begging water from the neighbours. I have started apologising in advance for the green fug and flies that could be my companions soon!

I have put my large bath mat in the spare bedroom, along with the camping toilet, and I will be able to have all-over washes. If things get too bad, I have access to my sister in law's weekend cottage, which has an electric shower. Luckily there is a launderette in the village, and I have a dryer! Hanging washing may be a bit difficult!
I lived in a Land Rover and tent for 4 months (albeit 30 years ago) so I know I can do it - you just need to look at what CAN be acheived.

Andrea