Water Softener vs Water Filter: Which Do You Need?
The most common confusion in water treatment. A softener removes hardness. A filter removes contaminants. Many homes need both.
These solve different problems
A water softener removes calcium and magnesium (hardness minerals) through ion exchange. A water filter removes contaminants like chlorine, PFAS, lead, and VOCs through carbon or membrane filtration. They are not interchangeable. A softener will not remove PFAS. A filter will not stop scale buildup.
How to know which you need
If your main issue is scale buildup, hard water spots, or soap that won't lather: you need a softener (or salt-free conditioner). Check your city's hardness level. above 120 PPM, a softener makes a measurable difference.
If your main issue is taste, odor, or specific contaminants (PFAS, lead, chlorine): you need a filter. The type of filter depends on the contaminant. carbon for chlorine and PFAS, RO for dissolved solids, certified filters for lead.
If you have both hard water AND contaminant concerns: you need a combo system (filter + softener). This is actually the most common situation for city water users. The filter is installed first to protect the softener resin from chlorine damage.
The decision framework
Start with your water data (use your city page on CheckMyTap). Look at two numbers: hardness (PPM) and contaminant flags. If hardness is above 120 PPM, you need softening. If contaminants are above health guidelines, you need filtration. If both. combo system.