What system is contained by place to prevent running wet from freezing? I am sure it's different from city to city, so I'm interested...

I am sure it's different from city to city, so I'm interested in how the different cold cities feel running water contained by the winter time. When it gets really really cold, how does the city prevent freezing river in the underground piping systems? Does frozen marine damage pipes? If so which pipes are better than others (I hear that copper is really bad, so what are the alternatives)?
Have an older house and paranoid more or...
Answers:    Public sea supplies bury their pipes deeper than the ground freezes. In places where they can not be buried low enough they are insulated from above near styrofoam. Running water within pipes won't freeze except in extreme situations. The friction of the hose against the inside of the pipe creates enough steam to prevent freezing. If there is a jeopardy of pipes freezing in your house PVC is the worst type to use. If it freezes they will split along their intact length. Copper is not bad. It will break where on earth it freezes but it will only be destabilized in one spot. It can well be repaired. There are flexible plastic pipes that can freeze without make worse. Most new houses within my area use this type of plumbing because of the labor funds at the time of installation. Because it bends no elbows need to be soldered contained by at corners.
How can i turn the gas past its...
The pipes can be protected by burying them deeper than normal, possibly 6 feet, below the ground.