How do you extend a water shutoff valve from a crawl space?

To extend a water shutoff valve from a crawl space, first, ensure the water supply is turned off. Use a pipe extension, typically PVC or copper, to connect to the existing valve, securing it with appropriate fittings and sealants. Route the extension through the crawl space and bring it up to the desired location, ensuring it is insulated if necessary. Finally, test the system for leaks before restoring the water supply.