You grew up in the tunnel-towns where the land-trains exhale, lit by the spill from the gates and priced out of the very water you helped load. A household's standing is its water tier; a debt is measured in days of supply. You learned the spot board before you learned your letters, and you learned thirst before either.
Choose one of the following skill boons.
A jury-rigged, patched, ugly little still that is unmistakably yours. Given time it wrings a mouthful of clean water out of almost anything: condensation, waste, a dead man's canteen.
You go markedly longer than others before dehydration bites, and you read the desperation in a room, a ration queue, or a haggle the way others read a clock.
You never leave a tap running. Ever.
A dripping tap drives you up the wall; you will cross a room, or a firefight, to stop it.