Fallout Wiki
Fallout Wiki

This is a great spot. With the right crew I'd have no problem keeping this place locked down.Sully's logs in Thicket Excavations

Pull the Plug is a side quest which occurs at the Thicket Excavations in Fallout 4.

Quick walkthrough

Side Quest: Pull the Plug
Talk to Sully Mathis.
Repair the underwater pipes by turning the three valves in the flooded quarry.
Start the pump.
Kill the two mirelurks and speak to Sully for the reward.
Reward: 200 XP
50-125 caps

Detailed walkthrough

Sully Mathis wants to unblock some underwater pipes at the Thicket Excavations. The pipes can be located by finding the bubbles on the surface and swimming down (water is irradiated, 10 per second). Each pipe can be fixed by simply turning a yellow valve located on the pipes. There are two exits from inside the dam, there is a lift and a staircase which are on opposite sides of the dam. The lift has a button at the top and bottom, and having it in the right position prior to navigating can be helpful. Underwater breathing boosts via the Aquaboy/Aquagirl perk or consuming a mirelurk cake is really not necessary, as the valves are not very deep underwater. The locations are in a triangular pattern; it helps to scope them out from above before diving in as the bubbles are clearly visible. A hazmat suit and/or some Rad-X helps counter the high rads.

After fixing the pipes and speaking to Sully, the player character must start the pump which will spawn two leveled mirelurks. The player may leave the zone and come back later or simply sleep 24 hours in the trailer right behind the big pump (and needs to be at least Level 12) to discover that the lake has been drained and occupied by raiders. At the very bottom of the dig site, the player character will find Sully (now a much tougher boss, having a minimum level of 30) and several mirelurks in pens. The mirelurks can easily be killed if the player character doesn't open the doors leading into their enclosures. In many cases, a single frag grenade should suffice. Sully seems to be breeding the mirelurks.

Quest stages

Quest stages
StageStatusDescriptionLog Entry
300 Repair PipesSully asked me to help repair the leaky pipes so he can get the pump running again.
500 Talk to Sully MathisI've repaired all the pipes. I should head back and let Sully know.
600 Start the pumpSully's giving me the great honor of turning the pump on. I just need to flip the switch.
700 Talk to Sully MathisThe pump's working! I should go talk to Sully.
1000 Come back later to see progressThe pump is running and the water is slowly emptying out of the Quarry. I should come back later and see what progress has been made.
1500Quest finishedWater lowered


  • Leaving the excavation zone before completing the quest will reset most of the containers on the location.
  • Inside the only lit trailer, the player character can find the "Thicket Excavations Terminal" which holds the "Sully's journal" holotape. The tape is priced at 888 bottle caps, which is unusual considering it is simply a personal journal.
  • Inside the same trailer there are at least two locked containers with modified weapons and chems.
  • With high enough Charisma, Sully can be haggled with three times for up to a reward of 125 caps.
  • If using power armor to navigate underwater, sometimes the water breathing effect does not occur when returning to it in certain areas which can result in drowning. It seems to be in regard to whether or not there is an underwater ceiling above one's head.
  • Using power armor while fixing the pipes can leave one at a disadvantage, seeing that it makes them hard to get to and traversing the underwater area takes considerably longer than quickly shutting off the pipes and returning later.
  • If Sully is killed before starting the quest, the quest can be started by turning the valves underwater, though the reward is fairly reduced.
  • If Sully is killed at any time before the raiders move in then his position will be filled with a leveled "boss raider."
  • As the player character is fixing the pipes to drain the water out of the quarry, one does not need to search underwater for loot but can just focus on fixing the pipes. The area is farmable upon revisiting on a set timer so one can feel free to wait.
  • Most companions, even those who normally like or dislike haggling attempts, have no reaction to any dialogue options in this quest.


  • Playstation 4Playstation 4 If one sleeps for 24 hours after killing the mirelurks but before talking to Sully, this quest's quest log entry will freeze and not go away.[verified]
  • Xbox OneXbox One Sully may only appear as a floating head and gun to fight the player character, while his inventory still shows that he is wearing cage armor.[verification overdue]