How to unlock: You must meet with Sully Mathis in Thicket Excavations (M1,5).
- Talk to Sully Mathis
- Repair the pipes
- Activate the pump
Meeting with Sully Mathis
Once you've arrived at Thicket Excavations search the area near the central pool of water to locate Sully Mathis. Talk to this person. You can agree to help Sully right away or you can use your high Charisma to demand a bigger reward - the maximum reward can be 125 bottlecaps.
Fixing the pipes
Your objective is to repair three pipes, but the problem is that they're underwater and the pool of water here is irradiated. Before you go into the water consume a Rad-X or put on an armor which will prevent you from receiving too much radiation. You can find the leaks quite easily, because there are bubbles on the surface above them. All of three areas you must inspect have been marked on the screenshot above.
Deal with the leaks in any order. Once you're close to the bubbles dive in and quickly find a pipe that needs repairing by turning a valve. Go back to the surface after you've succeeded and repeat this with the two remaining valves. Return to Sully once you've completed your task and activate the circuit breaker.
Activating the pump
You can't get the reward for this mission right away, because several softshell mirelurks will appear near the excavation site. Start attacking the monsters and make sure not to wound your ally by mistake. Once the area is safe again you will finally receive bottlecaps and the quest will end.
Quest rewards: Experience points, bottlecaps.
You need more or less 24 hours of the in-game time since the pump is activated to get rid of the water. If you want, you can return here (no new quest will appear in the journal) and start exploring the large territory that was previously flooded (travel through the narrow metal balcony or use the elevator).Thugs accompanied by guard dogs will appear in the location. What's interesting, Sully, whom you have helped previously, will be aggressive towards you as well - seems that he hid his true intentions. When exploring the empty tank, in addition to killing and looting bodies of bandits (Sully will have a good sniper rifle and some other items), you can also check the containers with items.