CORNERSTONE GUIDE

How to get safe drinking water at home.

Six steps that work in any home, on city water or a private well. No sales pitch, and every claim is sourced.

Step 1: Find out what's actually in your water.

On city water: every community water system must send customers an annual water quality report, called a Consumer Confidence Report, by July 1 each year. It lists where your water comes from, which regulated contaminants were detected, and any health-standard violations and what the utility did about them. Look for it on your water bill or your utility's website.

On a private well: no one tests it for you. The CDC recommends testing well water at least once a year for total coliform bacteria, nitrates, total dissolved solids and pH. Your local health department can tell you what else to test for where you live. Use a state-certified laboratory.

Step 2: Match the filter to the problem.

A filter is only as good as what it is certified to remove. Look for NSF/ANSI certification (an independent test that the product does what it claims) and check the specific product on NSF's online listings:

For PFAS ("forever chemicals"), NSF says to look for a certified PFAS reduction claim under NSF/ANSI 53 or 58, not just the manufacturer's label. A water softener is not a drinking-water filter at all; see

Reverse osmosis pushes water through a very fine membrane. Clean water passes through; the rejected water carries the removed salts, metals and most PFAS away. In a zero-waste design, the rejected water goes back to everyday use instead of the drain.

Step 3: Store it clean and cold.

Filtered water, especially reverse osmosis water, has little or no chlorine left to keep it fresh. Keep it in a covered glass carafe in the fridge, use it within two or three days, and wash the carafe every week.

Step 4: Keep up with filter changes.

Every filter has a rated capacity. Replace cartridges on the manufacturer's schedule; an overdue filter can stop removing what it was certified for. Price the replacement filters before you buy the unit.

Step 5: Skip the sales traps.

Color-change drops and "electrolysis" boxes at your door are not water tests. Never sign the same day, and know your right to cancel.

Step 6: Official notices come first.

If your utility issues a boil-water or do-not-drink notice, follow its instructions. A home filter is not a substitute for an official advisory.

Sources.