Every homeowner should know where their main water shutoff is before an emergency. For homes on city water, the shutoff is usually near the water meter — either in the basement, crawl space, utility room, or outside near the foundation. For well water homes, the shutoff is typically near the pressure tank. There\'s also a shutoff at the well itself (usually a disconnect box near the well head). In an emergency, shutting off the main valve immediately stops water damage from spreading.