Water Filter Buying Guide
Learn about different water filter types and which contaminants they remove.
How to Choose a Filter
- Test Your Water: Get your water tested or check your utility's Consumer Confidence Report
- Identify Contaminants: Know what contaminants you're trying to remove
- Check Certification: Look for NSF/ANSI certification for specific contaminants
- Compare Costs: Factor in purchase price and replacement cartridge costs
- Consider Installation: Pitcher, faucet-mounted, under-sink, or whole-house
- Plan Maintenance: Know how often you'll need to replace filters
Filter Comparison
Activated Carbon Filters
Removes:
- Chlorine
- Chlorine byproducts
- Some VOCs
- Odors
- Taste
Does NOT Remove:
- Minerals
- Bacteria
- Viruses
- Nitrates
Cost
$
Filtration Speed
Fast
Maintenance
Replace cartridge every 6-12 months
Reverse Osmosis
Removes:
- Most minerals
- Heavy metals
- Bacteria
- Viruses
- Nitrates
- Lead
Does NOT Remove:
- Beneficial minerals removed
Cost
$$$
Filtration Speed
Slow
Maintenance
Replace filters every 6-12 months, servicing every 1-2 years
Ion Exchange (Water Softener)
Removes:
- Calcium
- Magnesium
- Some heavy metals
- Radium
Does NOT Remove:
- Organic compounds
- Bacteria
- Most contaminants
Cost
$$
Filtration Speed
Medium
Maintenance
Regenerate with salt every 1-4 weeks
UV Filter
Removes:
- Bacteria
- Viruses
- Some protozoa
Does NOT Remove:
- Chemical contaminants
- Minerals
- Heavy metals
Cost
$$
Filtration Speed
Fast
Maintenance
Replace UV bulb annually
Whole Home Carbon Filter
Removes:
- Chlorine
- VOCs
- Some sediment
- Odors
Does NOT Remove:
- Minerals
- Bacteria
- Viruses
- Heavy metals
Cost
$$$
Filtration Speed
Fast
Maintenance
Replace cartridge every 6-12 months
Certification Matters
When buying a water filter, always look for certification from:
- NSF International (NSF/ANSI): Tests filters for specific contaminants and standards
- WQA (Water Quality Association): Certifies product quality and performance
- IAPMO: Tests plumbing products for safety and performance
A filter may remove lead, but unless it's certified for lead removal, you can't be sure. Always check the NSF certification number.
When to Replace Your Filter
Filter effectiveness decreases over time. Replace based on:
- Manufacturer's recommended schedule (usually 6-12 months)
- Water pressure decrease if you notice slower flow
- Bad taste or odor returning
- Water volume (if filter is rated for 100 gallons, replace after 100 gallons)
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