The Henry's have an artesian well on their property....they have water! A line is run from the Henry's spring/well to Randy Bragg's house whose water had ceased to run.
Mark Bragg is Gen. Hawker's intelligence aide. When it appears that the Soviet's are preparing a missile attack on the USA, he suggests to Gen. Hawker that he receive the "control" of the nuclear missiles/bombers under his command. Gen. Hawker does so and thus saves a few minutes that it takes to call the Chain of Command, which might take longer than normal in the event of an attack underway. Not long after receiving the release of the U.S. nuclear arsenal, a Soviet missile attack is detected and thus, Gen. Hawker can order an immediate retaliatory strike without any delay. (Not that mutual assured destruction is a victory.)