According to the farmers of Westside, Anderson's assistance in implementing a reliable irrigation system for Clayton Ettienne and the Westside Cooperative is the main reason why the community can grow crops so well, and therefore survive and encourage trade. One could argue that he is the main reason citizens there do much better than they do in Freeside.
Despite having the good opinion of most of Westside's citizens, Tom has a troubled past which attributes to his exile from the Followers of the Apocalypse. He has broken the law many times due to his belief in the maxim "the end justifies the means." Anderson has even committed murder, killing an NCR trooper to cover his diversion of water to Westside to prevent local crop failure. Unknown to him, the water is contaminated by radiation from Vault 34.
"I suppose there's no point in denying it any longer. I killed Corporal White to protect Westside's self-reliance. It was rash, and I regret it now. We don't have the money to pay for the water, so I rigged the pump station to divert water to the local cisterns from time to time."
ps3xbox360 Anderson can disappear into the wall of his apartment though he remains on your radar, if this happens prior to the White Wash quest, the quest becomes impossible to finish. [verified]
xbox360 Even though you can find him in the prison at the Camp McCarran terminal building at the end of the quest, you can still find him in Westside. There will be two non-player characters of Anderson. [verified]