After you arrive in Flatwoods and register with the Responders during the First Contact quest, you’ll have to complete a series of quests in and around the town to learn survival skills. While these are themed around learning the skills necessary to be a Responder, they’re also invaluable guides in how to deal with the new survival mechanics in Fallout 76. The first such quest, the Fallout 76 Thirst Things First quest, will teach you how to collect water and boil it to reduce the amount of rads.
How to Complete the Fallout 76 Thirst Things First Main Quest
You should start the Fallout 76 Thirst Things First quest immediately after completing First Contact. After using the registration kiosk to search for Kesha McDermott, head west through Flatwoods to the nearby river. Here you will find Kesha’s body. Search her inventory and recover her Holotape and Water Testing Kit. Then look at the river and select the option to “Collect”; be sure not to drink, as you’ll get much more radiation from drinking directly from water sources like this. Similarly, wading too deep into the river will start to apply radiation to you, so stick to the bank.
Once you’ve collected water for testing, head for the Flatwoods Community Garden. Here you can find a couple of water pumps where you can collect a second sample of water. Take the two samples back to the church, where you can find a homemade laboratory at the back of the hall. Use the terminal to “Analyse Water Sample,” which will inform you that the water is irradiated and must be purified. You can now use the Chemistry Workbench beside the terminal to boil the Dirty Water, turning it into safer Boiled Water. This isn’t as good as Purified Water, but it’s better than drinking straight from an irradiated water source!
With all the steps complete, head back across the street to the registration kiosk in the tavern to complete the quest. Doing so will reward you with a Chemistry Workbench plan, a random piece of armour, a random aid item, and random ammo. You will also start the next quest; Second Helpings.