Check our work
Run the boil test yourself tonight.
These are illustrations. When our own footage is cut, it replaces them here, and it will say so.
Measure a known volume
Two litres of cold tap water into a clean, dry, heavy-bottomed pan. Note the volume · the arithmetic depends on it.
Reduce it, do not scorch it
Simmer uncovered until roughly a centimetre of liquid remains. Drop the heat near the end. Scorching adds carbon and ruins the read.
Dry the film
Lowest heat until the last of the water goes. What remains is the dissolved solids from two litres. At 250 ppm that is half a gram. Your water will differ, which is the point of doing it yourself.
Repeat with filtered water
Same pan, same volume, same method. A carbon pitcher should look about the same. Reverse osmosis should look dramatically emptier. That difference is the entire claim.
Do not read this as a safety test. It measures dissolved minerals, not contamination. It is a demonstration of what a filter does and does not remove.