Flood is a gamemode in which you fight other players for survival over deadly water whilst staying alive via boats made up of various props. The goal of the game is to be the last man standing, and whoever wins gets a cash bonus.

Players start with a set amount of money (Decided by owner) and can earn money numerous ways, depending on the server; some servers have you earn money by surviving (1-2 cash per second while alive during the fight period) or by dealing damage to props (x cash for 1 damage done to a prop). The latest version of flood (2.01) has you earn money by dealing damage to props and winning rounds.