Crawlspaces, and the freeze problem that comes with them
Houses of this era sit over crawlspaces rather than concrete slabs. Supply lines run through unheated, vented space under the floor, which means they sit in outside air on a freezing night with only floorboards above them.
Two consequences worth knowing. The split normally shows up during the thaw rather than during the freeze itself, because the ice plug seals the break it created until it melts, which is why the damage often appears a day or two after the cold has gone. And the water drops into the crawlspace instead of pooling indoors, so the first sign is frequently a damp smell, a floor that feels soft, or sagging insulation rather than anything you can see.
Ahead of winter weather Spartanburg Water tells residents to let faucets drip, since moving water resists freezing far better than still water, and the utility has said publicly that it does expect some burst pipes and water line breaks during a freeze event. In crawlspace housing that advice is worth following, along with sealing crawlspace vents during a cold snap and taking garden hoses off outdoor taps in autumn. If a line has already gone, see frozen burst pipe repair.
