Different water problems need different solutions. Start by identifying the issue and testing your water rather than choosing a filter based on claims alone.
1. What’s your main water concern?
Lead or other dissolved metals
Use a certified laboratory to identify contaminants. For drinking water, compare point-of-use filters with an independently verified lead-reduction claim under NSF/ANSI 53 or appropriate reverse-osmosis systems certified under NSF/ANSI 58. A generic carbon filter is not automatically certified for lead.
Read our guide to hidden drinking-water contaminants.
Chlorine taste or odor
Look for a filter with a verified chlorine taste-and-odor reduction claim, commonly certified to NSF/ANSI 42. If chloramine is the problem, verify that specific reduction claim.
How to remove chlorine taste from tap water.
Rotten-egg smell
Hydrogen sulfide or other sources may be involved. Test first, then consider treatment matched to the confirmed cause; a simple drinking-water pitcher may not address a whole-home odor.
What causes a rotten-egg smell in water?
Private well, bacteria or nitrates
Use an accredited or state-certified laboratory and follow public-health advice. Filtration for dissolved chemicals differs from microbiological disinfection. Boiling can disinfect microbial contamination but does not remove lead or nitrates.
2. Choose where you need treatment
Under-sink or faucet filters: often a sensible starting point for contaminants in drinking and cooking water. Whole-house systems: may be appropriate for pervasive odor, sediment, or other confirmed issues at multiple fixtures, but do not assume whole-house carbon removes every hazardous contaminant.
3. Verify before buying
- Check a current water report or laboratory test.
- Verify the specific contaminant reduction claim in the certification body’s database, not just the presence of an NSF/ANSI standard number on a box.
- Compare cartridge replacement intervals, flow rate, maintenance costs and installation needs.
- Test the treated water where appropriate.
Want to test your knowledge first? Take our free interactive Water Safety Quiz.