Five pages
Standards
Three numbered standards, two certifying bodies, and the page about everything a certification mark was never designed to answer. The three cells of the chip on this site are the three numbers below, and nothing else fills them.
Read this before any of it
No filter in this catalog makes unsafe water drinkable. Household drinking water filters are designed for water that is already fit to drink. They are not intended for microbiologically unsafe water and they do not replace a boil water advisory from your utility or health department.
If you suspect lead or contamination in your supply, the next step is your utility's Consumer Confidence Report, the EPA, and your local health department. It is not a purchase.
The three numbered standards
NSF/ANSI 42
NSF/ANSI 42: taste, odor and particulate
The aesthetic standard. Chlorine taste and odor, and particles.
Aesthetic effects: things you can taste, smell or see. Chlorine taste and odor is the headline claim, and particulate reduction is graded by particle size class.
NSF/ANSI 53
NSF/ANSI 53: the health effects list
The health effects standard. Specific contaminants, certified one claim at a time.
Reduction claims for contaminants that the standard classes as having health effects. Lead is the best known of them, and a product is certified for the specific claims it was tested for, not for the whole list.
NSF/ANSI 401
NSF/ANSI 401: incidental and emerging compounds
A separate list of incidental contaminants. Its own number for a reason.
A defined list of incidental contaminants and emerging compounds, the group that includes certain pharmaceutical and pesticide residues found at trace levels in some supplies.
The two pages with no cell of their own
A certifying body is not a standard, and the gaps around a certificate are not covered by one. Neither of these fills a chip cell, which is exactly why each has a page.
IAPMO R&T and WQA
IAPMO R&T and WQA: bodies, not standards
Two certifiers. Naming one of them still leaves the standard number unsaid.
A listing naming IAPMO or WQA has named who did the work, not what the work was. The follow-up question is always the same: certified to which standard, for which claims? Both organizations publish searchable listings that answer it.
The gaps
What certification does not cover
The page that stops the other four being read as a guarantee.
Treat a certification as a bounded statement: this product, under this standard, for these claims, tested this way. Everything outside that boundary is unaddressed, and unaddressed is not the same as fine.