Ranked by combined water and energy use per wash. Closed-loop recirculation is highest; low-flow / mist next; a conventional pressurised shower lowest.
Solutions
Gravity-fed shower: Low pressure but passive, resilient to pump/power failure.
Pressurised mains-fed shower/bath: Standard fixture performance, fed from a pressurised supply. The fixture itself is just plumbing, it draws no power. The pressure it depends on is produced upst
Closed-loop recirculating shower: Draining shower water is caught, filtered, and UV-disinfected in real time (multiple times per minute) and immediately recirculated through the showerhead, topp