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Comment by alyx | Hacker News Reader

Maybe I didn't do a good job scanning the comments, but I'm surprised nobody (not even the article) mentions the NSF certification body.

Taste is important but very subjective. I don't buy a water filter unless it shows up as certified by NSF[1].

A few years ago I almost fell for a "water purification system" on Amazon, with stellar reviews that was supposed to filter out everything. With a baby on the way I figured it was worth the price tag. Good thing I did my research. The water filtration system was not certified or verified by anybody.

edit:

Same thing applies to humidifiers, air cleaners, air conditioners, etc. Don't buy unless it has been certified[2].

[1] http://info.nsf.org/Certified/DWTU/

[2] http://ahamverifide.org/

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Well, maybe it's a bit more complicated than that. It's certainly true that if you're using a water filter to remove something dangerous rather than remove "hardness" or "chlorination", then you're going to want a certification (and regularly test to see if the RO filter is still working). I'd put ship, cistern, and catchment on that list of critical filters.

However, if your decision is primarily based on flavor (as the article's is) or mineral build-up, then it's not clear that it's so important since you're drinking the water anyway!

I'd note that one brand you may be referring to (although it's true for others) has both "residential" and "professional" series. The latter are WQA Certified (NSF/ANSI 58 & 53)... although you won't find them listed on the NSF website, they are both ANSI and SCC (Canada) certified.

http://yourwaterfilterguide.com/difference-apec-water-reside...

https://www.wqa.org/learn-about-water/faqs

Thanks!!! Safety above taste seems obvious for a water filter.

Tap water has more stringent safety standards than bottled. So unless you live in flint, then safety shouldn't really be an issue.

Not just Flint.

https://www.wsj.com/articles/pittsburgh-tries-to-avoid-becom...

"A total of seven U.S. water systems, which each serve more than 100,000 people, had lead concentrations above the federal action level of 15 parts per billion in recent months, according to Environmental Protection Agency data. They include Portland, Ore., and Providence, R.I., which both exceeded the limit at least one other time in the past five years."

Or you could get a conductometer and measure the purity yourself.

What is the equivalent certification called for air cleaners?

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