Ask Water Merchant to help

Ask Water Merchant to help is an unmarked quest $$

Detailed walkthrough
To complete this quest, the Vault Dweller needs to go to the Water Merchants in the Hub and pay the master merchant, Martha Rastello, 2000 caps to supply Vault 13 with water. The Vault Dweller may be able to secure a better price of 1000 or even 500 caps, providing they can convince her the vault can sufficiently supplement the lower payment. After securing the deal, the time limit for finding the water chip will be increased by 100 days and it will also have an impact later in the game.

Rewards

 * 1000 XP
 * 100 more days to find the water chip