We are experiencing quite a cold week. My wife asked me if I had insulated the pipes the other night, but she meant the pipe on the exterior of the home. I have pipe insulation installed, which is kept on the pipe all year long. Many Houstonians will find their water supply pipe coming up from the ground under a hose bib. You will want all of this pipe from ground to into the house insulated.
You may not consider the pipes in your attic though. Many homes have uninsulated metal pipes in their attics. Pipes running in cold areas where they are not covered by insulation can freeze. It may be too late to cover these pipes with insulation now, so you may consider one trick: leave a tap slowly running. The flowing water should help prevent burst pipes. This method is not as good as insulating, but it can hlp.