Find the Water Chip

Find the Water Chip is a main quest in Fallout.

Vault 15

 * first Exit Vault 13 cave entrance.
 * Travel to Shady Sands, which is located on path to Vault 15.
 * Acquire some rope.
 * Pickpocketed or bartered from Seth.
 * Found in bookshelves, or traders.
 * Sold in the Hub's General Store at 20 caps.
 * Enter Vault 15 and use the rope on the broken elevator shaft.
 * On the second level another rope can be found in the locker in a side room on the way to the second broken elevator shaft.
 * Descend to level 3, enter the area were the command center should be, earn 500 experience for discovering the destroyed command center.

The Hub

 * Get the holodisk from Library.
 * (optional) Travel to the Water Merchants, and ask them to send water to Vault 13.

Necropolis

 * Travel to the Necropolis and enter the sewers.
 * Travel to Watershed area.
 * Bypass Harry with: a high Speech skill, Sneak or violence.
 * Speak to the imprisoned ghoul, and then enter the vault through the cell (with an actual door) located next to the ghoul's cell.
 * Travel to the third floor via the elevator and take the water chip from the command center.
 * Return to Vault 13 and give the chip to the overseer, Jacoren.

Detailed Walkthrough
Exit the cave entrance and travel towards Vault 15. Enter Shady Sands (the green circle denoting a location uncovered during the travel to Vault 15).

Shady Sands
Locate a rope:


 * The easiest way is to steal it from Seth at the entrance to Shady Sands. It can also be bought from him.
 * It can be found on certain bookshelves in Shady Sands.
 * Can be purchased from certain traders.

After acquiring the rope travel to Vault 15.

Vault 15
The vault entrance is hidden in the uninhabited shack. Open the hatch and descend into the vault.

There are a few giant rats in the area. Head towards the broken elevator, and use the rope on the shaft. Use the rope to descend to the second level.

Scavenge the area for loot, including a Colt Rangemaster hunting rifle, a leather jacket and another rope (inside the locker). Use the rope on the second shaft and descend to the third level.

Proceed to where the command center should be. Once it is in sight, 500 XP are awarded for verifying that it is not salvageable.

The Hub
After coming out of Vault 15 empty handed, travel to the Hub. Ask Ian for directions.

Enter the large building labeled Water Merchants, and speak to the Master Water Merchant.


 * If pressed about Necropolis she will reveal its location. Alternatively, Miss Stapleton sells a holodisk with the location of Necropolis.
 * (optional) She can send water to Vault 13 for varying prices. This will add another 100 days to the time limit.

Travel to Necropolis.

Necropolis
Use the manhole to enter the sewers and proceed to the Watershed area. Find a building with some super mutants and an imprisoned ghoul. In order to navigate the area without combat, either convince the super mutant leader Harry with a high speech skill or sneak past. Violence is always a solution.

After dealing with the super mutants, free the Ghoul prisoner (if he is still alive) and he will identify the entrance to Vault 12 in the adjacent cell. It can be opened without speaking to him.

Vault 12
Ghouls inhabit the Vault area and are hostile during nighttime. Travel to the third level using the elevator. Enter the command center area. Remove the water chip from the computer. This action will cause the ghouls in the Vault to turn hostile, though.

After you obtain the chip, head back to Vault 13 and give the chip to Overseer Jacoren.

Rewards

 * 500 XP for finding the destroyed command center
 * 7000 XP for giving the water chip to Overseer Jacoren

Related quests

 * Destroy the source of the Mutants
 * Destroy the Mutant leader
 * Find the Water Thief

Bugs

 * For keeping the water chip, simply press the 0 button when the Overseer asks you for it. Afterward you will be at the computer, gain the 7500 xp, lose the time limit, get the new quests from the Overseer and keep the chip. If you have a Bag or Back Pack below the Water Chip in your inventory list this will also keep the chip from disappearing.
 * There are two ways to "reset" this quest. The easiest is to talk to the Water Merchants. The other requires that you kept the chip: returning to Necropolis and using it on the water computer there will also undo the chip quest, which means you can give the water chip to the Overseer again for 7500 more XP. Using the cheat to keep the chip you could travel between the Hub and Vault 13, gaining 8500 XP each round trip and increasing the time limit all the while.