Take This to the Store
Even if you decide not to take my advice on which filter systems to buy, please print this checklist and take it with you when you go shopping. At least you'll know the right questions to ask and won't be fooled by vague marketing claims.
— Keith Wilks, Filter Authority
🔍 Water Filter Red Flags Checklist
Questions to ask before buying any water filter • filterauthority.co.uk
"Even if you don't buy the filters I recommend, use this checklist to ask the right questions. Don't let vague marketing claims fool you." — Keith Wilks, 24 years in water filtration
When You See These Claims, ASK:
"50% better filtration"
Ask: 50% better than WHAT? Which contaminants? Verified by whom?
"Removes impurities"
Ask: WHICH impurities? At what percentage? Is there NSF certification?
"Good for hard water areas"
Ask: Does it actually SOFTEN water or just improve taste? Does it prevent limescale?
"Helps water taste better"
Ask: Does it have NSF 42 certification for chlorine/taste removal?
"Reduces contaminants"
Ask: Reduces by HOW MUCH? 10%? 50%? 99%? Which specific contaminants?
What GOOD 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"
NSF Certification Quick Reference:
| Certification | What It Means |
|---|---|
| NSF 42 | Taste & odour (chlorine) — basic improvement |
| NSF 53 | Health contaminants (lead, cysts, VOCs) — important! |
| NSF 58 | Reverse osmosis systems — comprehensive removal |
| NSF 401 | Emerging contaminants (pharmaceuticals, pesticides) |
| NSF P473 | PFOA/PFOS (forever chemicals) |
✅ Before You Buy, Ask These Questions:
Free resource from Filter Authority • filterauthority.co.uk
Independent advice from Keith Wilks, 24 years in water filtration