Vault 99

Experiment
Vault 99 was meant to test how the residents reacted when under constant danger of flooding. Various systems constantly crashed throughout the vault, causing water from the nearby James River to leak in, flooding the vault. Vault-Tec hadn't informed the Overseers about this, and thus they were drastically under prepared when the vault started to break down and flood.

Result
Vault 99 was maintained by the residents for 200 years, until in 2275 the residents gave up on fixing it. The Overseer ordered all of the residents to evacuate the vault and grab whatever they could. The residents of Vault 99 fled to the surface, where they found the ruins of Newport. Their first encounters with the wildlife and raider groups led them to believe the world to be anarchy. However, instead of trying to fix the problem, the Overseer decided that the vault's best chance at survival was to adapt, and thus the Newport Raiders were created in 2278 in the ruins of Newport.

The Newport Raiders spread, using the still flooding Vault 99 as a resource for a year until in 2276 the flooding got so out of hand that it started to overflow out into the streets of Newport, forcing them to close the vault door for good in order to stop the vault from flooding the entire city. Now, Vault 99 is inaccessible, with all the electronics connected to the door controls from the outside broken, shutting the door for good. If Vault 99 were reopened, there would be a possibility that it could flood much of Newport.