Prepper Stash: Deep Dive
A prepper stash at the Laurel Residence, south and a wee bit west of Fall's End, in John's region.
The stash note is on the kitchen counter inside.
Head south to the shed, and bunker door.
As the note by the door indicates, the shed key is underwater in the bunker. Dive down to get it- the key is in the far right corner of the room, on a table by a flashlight.
Grab it, and head back up. You don't need the underwater breathing perk here, just don't dawdle.
Unlock the shed, and throw the electrical switch inside.
You'll see an output pipe start spraying as the bunker drains. Go back down- there's still a bit of water left, but you can now wade across the room to smash through the wooden barricade.
This give you access to the stash, and completes the mission.