The basement is the mechanical and emergency core of the Bath House — housing water heating infrastructure, greywater processing, NBC-compatible ventilation, and a self-contained emergency shelter nook with sleeping, sanitation, and supplies. Two hardened underground tunnels connect this level to the compound network: Tunnel B runs Bunker-to-Bunker directly to The Fortress; Tunnel C connects to The Station. Decontamination entry is on the ground floor above.
- Dual solar thermal water storage tanks — ~1,000 L each with backup
- Backup boiler — wood or biogas fired
- Greywater processing system
- NBC-compatible ventilation — dual shafts and blast doors
- Sealed operation during chemical or biological events
- Tunnel B access point — Fortress Bunker-to-Bunker; blast door, fiber and power conduits, emergency lighting
- Tunnel C access point — Station direct link; blast door, fiber and power conduits, emergency lighting
- Towels, soaps, and cleaning supplies
- Emergency rations
- Seed bank — long-term storage
A self-contained emergency space within the basement — sleeping, sanitation, and food preparation independent of the floors above.
- 2 Murphy bunks — foldout sleeping for 2
- Fold-out couch — additional sleeping surface
- Compact kitchenette — food prep during shelter
- Full bath — shower, toilet, and sink