What we cover
Eight topics, one method: what each type of system can do, which certification backs it up and how to tell whether it fits your home.
Water Softeners
Hard water leaves scale on fixtures and appliances. A softener is sized by your water’s hardness and your household’s daily use.
NSF/ANSI 44
Whole-House Filters
Point-of-entry systems that treat every tap. Flow rate and certified claims matter more than the number of stages.
NSF/ANSI 42 · 53
Under-Sink & Reverse Osmosis
Point-of-use systems for drinking and cooking water, from carbon filters to reverse osmosis.
NSF/ANSI 53 · 58
Refrigerator Filters
Match the filter to your fridge’s model number, then check what it is actually certified to reduce.
NSF/ANSI 42 · 53 · 401
Shower Filters
Most shower filters target chlorine. The certified claim to look for is free chlorine reduction.
NSF/ANSI 177
Well Water
The EPA doesn’t regulate private wells, so testing, treatment and upkeep are up to the owner.
Test first
Water Testing
Utility reports, certified labs and home test kits: how to find out what’s in your water before you treat it.
Certified labs
Contaminants
Lead, PFAS, nitrate, arsenic and more: what the EPA allows, and how a legal limit differs from a health goal.
Limits vs. goals
Start with your water
The right system depends on what’s actually in your water, so check before you buy anything.
On city water
Your utility publishes an annual Consumer Confidence Report that lists the contaminants it detected and the limits that apply.
On a private well
No one tests a private well for you. The EPA explains what to test for, and certified laboratories can run the tests.
How we grade
Every guide follows the same four rules.
Certification first
We check each claim in the certifier’s own listing (NSF, WQA or IAPMO), not on the box.
Manufacturer data
Capacity, flow rate, filter life and replacement costs, taken from the data sheet and the manual.
No invented tests
We don’t run lab tests or publish made-up scores. What isn’t verified isn’t presented as fact.
Primary sources
Health figures come from the EPA, the CDC and the USGS, with legal limits kept apart from health goals.
Who runs this site
Certification over claims.
“If a system is certified, I show you what it’s certified for. If I couldn’t verify something, I tell you that too. That honesty is the whole point of this site.”
John — Founder and Lead Writer, WaterGradePro (avatar created with AI). NSF/ANSI certifications, EPA and CDC data, and the manufacturer’s own manuals behind every recommendation. How I work →
No-hype policy: no invented tests, no paid placements
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