Thirst Things First

Thirst Things First is a main quest in Fallout 76.

Background
Although the Responders are deceased, their automated courses still remain active and can be used by Vault Dwellers to become officially certified volunteers. In Flatwoods, volunteers can begin their work by completing Kesha McDermott's water tests.

Quick walkthrough

 * Search for Kesha McDermott along the nearby river.
 * Retrieve the water testing kit from her remains.
 * Test water from the river in Flatwoods.
 * Test water from a water pump in Flatwoods.
 * Analyze the test results in Kesha's lab.
 * Make boiled water at a cooking station.
 * Check back in at a Responders self-serve kiosk.

Detailed walkthrough

 * This is a tutorial quest introducing the basics of survival. One has to first find Kesha's body over by the river, curled up on the bank. Her location can also be obtained from the self-serve kiosk, after accessing the people's directory.
 * There will be a water test kit on her body. After procuring it, one must sample two locations, one at the river nearby, the other at the water pumps located at the edge of town near the farms. Activating the water source by collecting or drinking will collect a sample.
 * Following this, one must return to the church and upload the sample to Kesha's terminal behind the automated vendor. This will lead to the conclusion that water must first be boiled to be made potable. Then one will gather wood and two units of dirty water, subsequently using any cooking station to make boiled water.
 * Revisiting the kiosk will end the quest. Halfway through to volunteer status!