Obviously depending on how your plumbing system is currently installed, you might be able to segregate your existing piping so that you would have water running to some parts of your house while you refit piping to the others. My guess would be that there is a branch fairly close to the supply line. Turn off the main shutoff (hopefully there is one and you don't have to call the water company) and cut off one branch to redo that side and cap off the stub you left. Then turn the main shutoff back on. Obviously, it would be helpful to know which is which to begin with so that you don't leave yourself with nothing but one functional sink, but, worst case, you can still take a, um, "sailor's bath".