Condensing Coil

• Take a length (3 feet or greater) of clean plastic tubing or clean soft copper and attach it over an opening in the lid of a tight-fitting metal pot. A pressure cooker lid is ideal for this, slipping the tube for a snug fit over the pressure relief post. In a pinch, use the hole for the lid handle and tape or epoxy the hose for a tight seal.
  
  

Heating Chamber

• Put the water in the metal pot, roughly half-filling the pot. Begin heating the pot in the open to release any volatile compounds in the water. When the water is near-boiling, attach the lid and coil and stabilize the temperature if possible to keep the chamber right at the boiling level.
  
  

Collection

• As water vapor passes through the condensation coil, driven by pressure in the heating chamber, some of the vapor will condense into pure water. Place a clean container at the outlet of the condensation coil to collect the resulting hot water.
  Increase the condensation efficiency by running at least part of the condensation coil through cool (may be unclean) water and by placing the collecting container lower than the heating chamber.
  
  If you keep the collected water away from contamination, it will be safe, drinkable water.