How to filter water twice if you live in the US

The water you drink is usually treated with chlorine, which is good because it kills pathogens.

But if it’s not, your water will be contaminated with other bacteria, viruses and pollutants, and your immune system will be at risk.

If you’re already sick and can’t afford to buy new filters, the best bet is to buy a filter that comes with a warning label to tell you what to expect.

Here’s how to know what to look for.