If you have a gas tank and a water barrel next to a lake you can get infinite clean water. Steps follow.
- Build a fluid barrel near a natural water source.
- Have a gas tank in your inventory and equip a combat pack so you can carry a full gas tank.
- Fill the gas tank from the water source.
- Deposit the water into the fluid barrel
- The water in the barrel will be clean.
- Endure the flames of wrath when you report the issue.