The Water Merchants control the water tower and, by extension, water distribution in the area. Their control over the oasis was the root of the Great Merchant Wars and remained a point of controversy among the Hubbers for years to come as rival companies were forced to buy water to sell from the WM. As such, this company became very wealthy, very fast, at the cost of developing some serious enemies, among them Decker of the Hub underground.
They also had some dealings with the Brotherhood of Steel, where their slimier side was shown. They attempted to exchange a large volume of water for a stockpile of weapons held by the reclusive faction. When the Brotherhood declined the offer, the Merchants sent thieves to take the weapons anyway. Their involvement came to light when the raiding party was caught. Luckily for the caravan house, the Elders downvoted the proposal of a reprisal action.
 Interactions with the player character
The head of the Water Merchants in 2161, Daren Hightower, is marked for termination by Decker, likely as part of his campaign to take over the water monopoly and rule the Hub abusing control of the water tower.
Compared to other companies, the caravan guards get the worst paycheck (only 200 caps each way) although they are less likely to run into fierce opposition, and leave on the 5th, 10th, 15th, 20th, 25th, and 30th of every month. Additionally, a shipment of water can be bought to send it to Vault 13 and extend the time limit for finding the water chip by 100 days. In the Vault Dweller's memoirs he mentions organizing water to be sent back to Vault 13, admitting in hindsight it was probably a mistake, but put his mind at ease. In the unpatched version, this also lowered the Vault 13 invasion time limit by 100 days.
The Hub was a larger city than both Junktown and Shady Sands combined. You could drop the Vault in there, and you probably would not notice. But the people of the Hub had no life, and it was a desolate place just the same. It eased my mind, however, to hire some merchants to bring water to the Vault. Looking back, it was probably a mistake to do so, but I was still innocent of the evils that lurked through the ruins of civilization. - Vault Dweller's memoirs
- ↑ Maxson: "You can't trust them. A few years ago, they offered us Water for a huge stockpile of weapons. We told them no, and you know what they did? Sent in thieves to steal the weapons! We caught 'em, but the Elders voted down going to the Hub to teach the merchants a lesson."