A method for pumping water on a naval vessel is disclosed, the method including but not limited to pumping fresh water from a fresh water reservoir into a fresh water flush tank; pumping salt water from a salt water reservoir into a fire water reservoir during fire operations; controlling a valve in liquid communication to alternately connect the fire water reservoir to the salt water reservoir to supply salt water to the fire water reservoir during fire operations and connecting the fire water reservoir to the fresh water flush to flush salt water from the fire water reservoir after fire water operations. A system is disclosed for practicing the method.