Certain sections of the sewer system are inhabited by vagrants who have retreated from the city above. Living in the underbelly of New Vegas, many survive by hunting rats for food and gambling off the fights at The Thorn. Others are prospectors who make journeys into the unsafe parts of the sewers. Most of these people speak to the player in depressed tones and occasionally warn of the Fiends taking over parts of the sewer system.
The New Vegas sewers only appear in Fallout: New Vegas.