Infestation

Overview

Infestation is an occurence in which a high concentration of zombies appear on a randomly determined location (either a building or an outdoor spot). An infested location becomes the gathering spot for a large group of zombies, equivalent in size to 1-2 hordes, as well as 1-2 Screamers.

If a large number of infestations exist on the map, survivor morale will begin to decline periodically until most of the infestations are cleared. In addition, if enough infestations exist on the map, hordes of zombies will attack the player's home base.

If an Infestation stays undisturbed for long enough, it might trigger a Seek And Destroy mission, where a survivor waits for the player to come and aid them to clear the infestation.

Even though they can be a nuisance, Infestation areas are also great spots for training Fighting or Shooting skills. Due to the high concentration of zombies, it is easy to score bonus XP for consecutive kills called feats such as Slaughter, Headshot Streaks or Multi-kills.

State of Decay 2 usually has infestations up to 6 zombies and 3 Screamers late in progression. Other zombies that pass the infestation get counted to the infestation zombie count, and must also be killed.

Strategy

Spotting Infestations

Because of their effect on Morale, it is advisable to regularly keep an eye out for infestations. They can be spotted using survey points, or by moving into close proximity to them. It is also possible to spot an infestation using the map: If previously a known location on the map (e.g. a Resource building, building with Nothing Left or an unlooted House) changes to an unknown location (a grey square), then it is certain that an Infestation has taken place in that location.

State of Decay 2 marks the infestations automatically, and will both exist on the map and notify the player.

Clearing Infestations

In order to clear an infestation, the player must kill all Screamers and eliminate or drive all zombies away from the area.

With an inexperienced survivor, it is safest to use a vehicle to lure most of the zombies out of the building and run them over, then head inside and kill the remaining few. Having another survivor for backup is recommended.

Since the zombies stand in close vicinity of each other, grenades and other explosives are quite useful for clearing infestations. A single well-placed grenade is sometimes able to clear an entire house, or at least eliminate most of the zombies. A more economical way is to use a Shotgun, in the hand of a survivor specialized in this weapon. A well-placed blast or two at the zombies closely clumped together usually wipe out most of them.

If they player can spare the Influence, artillery strikes are very useful and fun to watch, as is the Call For Backup support option which evens the odds against the large numbers of zombies.

If the player decides to clear the Infestation on foot, care must be taken to eliminate the Screamer(s) first, as their scream will draw nearby zombies and, more importantly, temporarily paralyze the survivors and drain their stamina, making them vulnerable to the zombie mobs nearby.

In case the infestation is located in one of the storages that can be found next to a house, the player should see if there is a propane tank next to one of the walls of said storage; since storages are small buildings, zombies will be confined inside and the explosion of a propane tank will most likely clear the infestation out, regardless of the zombies being inside or outside the storage. In order to make the propane tank explode the player needs a firearm; it is recommended to shoot at the tank from a safe distance so the survivor doesn't take damage from the explosion, and leave the area quickly, as the explosion will draw nearby zombies.

Notes

Police Cruiser is the most effective vehicle at drawing out zombies thanks to its siren in addition to the horn.
Screamers are known to stray outside of the boundary of an Infestation, not only spawning another in the infestation to take its place, but also letting that stray Screamer run free.