Once the player can return to the area, they may start looking for a red tent underneath the overpass, near the ramp leading up from the area. There, the player will find a prospector named Steiger standing near the hatch. Steiger warns them that the sewers are a dangerous place crawling with mutants, but he also mentions that the mutants have stored their loot in the sewers, suggesting that the player might find several valuables.
The exit from the sewers is across the road, near the Wasted Garage.
Once you enter the sewer, you will placed in a medium-sized room. Make sure you crouch right away, to avoid the mutants' attention. Directly in front of you, on the floor, is a corpse. Loot it, and then slowly approach the first mutant. Use the Striker Crossbow take him out silently. Doing this correctly won't attract the attention of the nearby Club Mutants. Loot the corpse next to the dead mutant. From here, head left into a small storage room. Grab whatever you can sell, and prepare for a firefight.
If possible, the Nail Gun's Railgun Slugs can take out two unsuspecting mutants, given it is aimed correctly. If the player is not in the possession of the Nail Gun, then the Combat Shotgun will work fine. Once you've killed them all, head down the stairs, and look the corpse. Progress to the platform opposite the one you came from. Loot the corpse on the ground, and head up the stairs.
From here, head through the tunnels. Some mutants will be waiting up ahead. Take them out, and proceed. You will eventually reach an exit. Head up the steps and climb the ladder.
- It's impossible to access the sewers without talking to Steiger first.
- The Ark Area Sewers is (most likely) the first of the sewers the player would visit.
- Near the start of the Sewers there will be a rush of Mutants. If the player is positioned behind a long railing, the Mutants will climb over that railing. During the time they climbing, they cannot attack or defend, and the player can easily kill them using their fists. Since there is a short interval between the Mutants streaming at the player, it is possible to just hold ground and defend the railing, and in that way kill the Mutants without firing a single shot.
- The Ark Area Sewers is the only sewer to feature a non-player character (Steiger). This is likely because It is considered the "first" sewer.
- This is arguably the shortest of the Sewer missions.