Firewater retention refers to the practice of storing water on a site or facility for use in case of a fire emergency. The stored water is typically contained in tanks or reservoirs and is used by firefighters to extinguish fires or to cool down structures to prevent further damage. Firewater retention is a critical safety measure in industrial facilities, especially those that handle hazardous materials. In some jurisdictions, firewater retention is mandatory and regulated by law. The amount of water required for firewater retention is typically determined by the size and hazard level of the facility. Regular inspections and maintenance of firewater systems are also necessary to ensure that they function properly in the event of a fire emergency.