A salesman dips a little pen into your water and a scary number appears. It works every time — and it measures the one thing you shouldn't be afraid of. Play it through and watch the con from the inside.
A digital readout feels objective. That's the trick — the meter is precise about a number that has almost nothing to do with whether your water is safe.
A test isn't dangerous because it's inaccurate. It's dangerous when it measures the wrong thing — perfectly.
The meter wasn't lying. 340 ppm was true. It just answered a question you never asked. The things that send people to the doctor — lead, arsenic, PFAS, bacteria — are measured in parts per billion and trillion. This meter reads in parts per million, and it cannot see any of them. Honest testing starts by matching the test to the worry. That's the next page.