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"I was in a hardware store last week, watching a young couple read the back of a water filter box. They were nodding along to claims like '50% improved performance' and 'helps reduce contaminants.' I wanted to tap them on the shoulder and say: 'Do you know what any of that actually means?'"
They didn't. And honestly, you're not supposed to. These claims are deliberately vague. They sound impressive while committing to absolutely nothing. After 24 years in this industry, I've watched marketing departments get increasingly creative at saying nothing while appearing to say everything.
Here's the uncomfortable truth: most marketing, not just in the water filter market, is designed to make you feel confident without giving you any actual information. It's not illegal—it's just... unhelpful. And when you're trying to protect your family's health, "unhelpful" isn't good enough.
Let me show you exactly what to look for—and what to ignore.
The Vague Claims Playbook
These are the phrases I see on almost every water filter package. They sound great. They mean almost nothing. Here's how to decode them:
"50% better filtration"
The Problem:
50% better than WHAT? Their old filter? A competitor? A sock?
What to Ask:
50% better at removing which specific contaminant, compared to what baseline, verified by whom?
Reality Check:
Without a comparison point and independent verification, this number is meaningless.
"Helps water taste better"
The Problem:
So it still tastes bad, just... less bad?
What to Ask:
Does it remove chlorine? By how much? Is there an NSF 42 certification?
Reality Check:
Any carbon filter will improve taste somewhat. The question is how much and for how long.
"Good for hard water areas"
The Problem:
Good for what exactly? Taste? Limescale? Scale prevention?
What to Ask:
Does it actually soften water or just improve taste? Does it prevent limescale buildup?
Reality Check:
Most filters don't soften water at all. Only ion exchange or water softeners actually reduce hardness.
"Removes impurities"
The Problem:
Which impurities? All of them? Some? The easy ones?
What to Ask:
Which specific contaminants are removed? At what percentage? Verified by whom?
Reality Check:
A coffee filter 'removes impurities' too. This claim tells you nothing useful.
"Pure, clean water"
The Problem:
Pure compared to what? Tap water? Pond water?
What to Ask:
What's the TDS reading before and after? Which contaminants are actually removed?
Reality Check:
Only reverse osmosis or distillation produces truly 'pure' water. Most filters don't.
"Reduces contaminants"
The Problem:
Reduces by how much? 1%? 50%? 99%?
What to Ask:
Which contaminants? What percentage reduction? Is there NSF 53 certification?
Reality Check:
Even a 10% reduction technically 'reduces' contaminants. You need specific numbers.
Spot the Pattern
Once you see it, you can't unsee it. Vague marketing claims follow a predictable formula:
The Formula:
- •Comparative without comparison: "Better," "improved," "enhanced" — but compared to what?
- •Vague verbs: "Helps," "may," "can" — weasel words that commit to nothing
- •Undefined terms: "Impurities," "contaminants," "toxins" — which ones exactly?
- •Impressive numbers: "99.9% effective" — at removing WHAT?
What Real Claims Look Like:
- "Reduces lead by 99.3% (NSF 53 certified)"
- "Removes chlorine taste and odour (NSF 42)"
- "Tested to reduce PFOA/PFOS by 95% (NSF P473)"
- "Filter life: 6 months or 1,500 litres, whichever comes first"
Notice the difference? Real claims are specific, measurable, and independently verified. Vague claims leave room for interpretation—which is exactly the point. And not just in the water industry.
What Actually Matters: NSF Certifications
Forget the marketing fluff. These are the certifications that actually mean something—because they're independently tested and legally binding. If a filter claims NSF certification, you can verify it at nsf.org.
| Certification | What It Tests For | Why It Matters |
|---|---|---|
| NSF/ANSI 42 | Aesthetic effects - chlorine taste and odour, particulates | Good for taste improvement, but doesn't address health contaminants |
| NSF/ANSI 53 | Health effects - lead, cysts, VOCs, specific contaminants | This is what you need for actual health protection |
| NSF/ANSI 58 | Reverse osmosis systems - comprehensive contaminant removal | The gold standard for removing virtually everything |
| NSF/ANSI 401 | Emerging contaminants - pharmaceuticals, PFAS, pesticides | Important for modern contaminants not covered by older standards |
| NSF/ANSI P473 | PFAS removal - specifically tests for forever chemicals | Essential if PFAS is your primary concern |
Want to understand certifications in depth?
I've written a complete guide explaining what each NSF certification actually tests for, how to verify them, and which ones matter for your specific concerns.
Read: Water Filter Certifications Explained5 Questions to Ask Before Buying Any Filter
What specific contaminants does this remove?
If they can't list specific substances with specific percentages, walk away.
What NSF certifications does it have?
No certification? No independent verification. You're trusting their word alone.
What's the filter capacity in litres?
'6 months' means nothing if you use more water than average. Get the actual number.
What's the flow rate?
Some filters are painfully slow. Know what you're getting into.
What does it NOT remove?
This is the question they don't want you to ask. A carbon filter won't remove lead. An RO system won't add minerals. Know the limitations.
My Honest Take
Look, I'm not saying all filter companies are trying to deceive you. They aren't. But, in my opinion, the industry has developed a language of vagueness that seems to benefit manufacturers at the expense of consumers.
The good companies will tell you exactly what their filters do and don't do. They'll have NSF certifications prominently displayed. They'll give you specific numbers, not marketing fluff.
The others will hide behind phrases like "advanced filtration technology" and "proprietary filter media" without ever telling you what contaminants they actually remove.
Your job is to tell the difference. And now you can.
— Keith (who's read more filter packaging than any human should have to)
Frequently Asked Questions
What does '50% better filtration' actually mean?
This claim is meaningless without context. 50% better than what? Their previous model? A competitor? A piece of cloth? Always ask: 50% better at removing WHAT contaminant, compared to WHAT baseline, verified by WHOM?
What should I look for instead of marketing claims?
Look for NSF/ANSI certifications (42 for taste/chlorine, 53 for health contaminants, 58 for reverse osmosis, 401 for emerging contaminants). These are independently verified and legally binding.
Are water filter marketing claims regulated in the UK?
The Advertising Standards Authority (ASA) regulates advertising claims, but enforcement is reactive. Companies can use vague language like 'helps improve' or 'may reduce' without specific proof. Only NSF certifications require independent laboratory verification.
What does 'removes impurities' mean on a water filter?
This is deliberately vague. 'Impurities' could mean anything from visible sediment to chlorine taste to dangerous heavy metals. A filter that removes sediment can legally claim to 'remove impurities' even if it does nothing for lead, bacteria, or chemicals.
How can I verify water filter performance claims?
Check for NSF certification numbers on the packaging or manufacturer's website. You can verify certifications at nsf.org. Also look for independent lab test results from organisations like TechGearLab or consumer testing bodies.
Ready to Find a Filter That Actually Works?
Now that you know how to read marketing claims, let's find a filter that matches your actual needs—with real certifications and verified performance.
Related Reading
Disclaimer: This article represents my professional opinion based on 24 years in the water filtration industry. While I've made every effort to be accurate, marketing practices vary by company and region. Always verify certifications directly with NSF or the relevant certification body. Last updated: January 2026.