Fill a large pot with tap water
Place a heat-safe bowl inside the pot so it floats above the bottom
Cover the pot with an inverted lid
Put ice on top of the inverted lid
Heat the pot until the water simmers
Let steam rise, condense on the lid, and drip into the bowl
Turn off the heat when enough water has collected
Let everything cool before handling
Pour the collected water from the bowl into a clean container
Store the distilled water in a sealed, sanitized bottle