Fix it

Step 2: Choose a Filter or Softener That Fixes It

Match the treatment to the problem, then check the certification listing before you buy: a claim on the box is not a certificate.

What's in Your Water

Lead in Drinking Water: Sources, Testing and Filters That Work
Where lead in tap water comes from, what the 2024 lead rule changes, how to check your service line and test, and how to pick a filter certified for lead.
Strong evidence

Reverse Osmosis

Best Reverse Osmosis Systems, Checked Against Their Certifications
We checked six popular home RO systems against their NSF, WQA and IAPMO listings: what each is certified for, filter costs, wastewater and who it suits.
How Reverse Osmosis Works: What It Removes and What It Wastes
How a home reverse osmosis system works, what it removes and misses, how much water goes down the drain, and how to tell if you need one.

Water Softeners

Hard Water: What It Does (and Doesn't Do) and How to Fix It
Hard water is calcium and magnesium, not a health hazard. What it does to pipes, skin and hair, how to test it, and when a softener is worth it.

Next step: Compare filters by certification →Picked for the "fix it" step.