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FilterScored

Contaminant · Water

Mercury

EPA MCL 0.002 mg/L (2 ppb). 9 of the water filters we score hold an accredited NSF, WQA, or IAPMO certification to reduce Mercury, and 6 more market it with no accredited certification we could verify. A claim is not a certification.

What it is

Mercury is a naturally occurring heavy metal that can dissolve into groundwater and surface water. It enters drinking water from natural mineral deposits, discharge from refineries and factories, and runoff from landfills and croplands. Because it carries no taste, color, or smell, mercury in tap water is detected only by laboratory testing.

Why it matters

The EPA sets a federal maximum contaminant level (MCL) for mercury of 0.002 mg/L, which is 2 parts per billion, in public drinking water. That number is a regulatory reference point for the amount allowed in treated water, not a line that describes any individual filter's performance. We score whether a filter is certified to reduce mercury, not any health outcome.

What removes it

Mercury reduction is certified two ways: under NSF/ANSI 58 for reverse osmosis systems, and under NSF/ANSI 53 for select activated-carbon filters whose media is specifically formulated to bind mercury. The trap is that ordinary carbon filtration certified only under NSF/ANSI 42 targets taste and odor and is not certified for mercury. So a pitcher or cartridge earns credit here only when it carries an NSF/ANSI 53 or 58 certification that names mercury specifically, not a general carbon claim.

Reference: EPA National Primary Drinking Water Regulations, mercury MCL 0.002 mg/L; NSF/ANSI 53 (drinking water treatment units, health effects) and NSF/ANSI 58 (reverse osmosis).

Scored filters certified for Mercury

Marketed for Mercury, but not certified

These scored filters market Mercury reduction but we found no accredited NSF, WQA, or IAPMO certification for it - "tested to" is not "certified to." Absence of certification is not proof a product fails to reduce it, only that we found no independent verification.

FAQ

Does a Brita or carbon pitcher remove mercury?
Only if that specific pitcher is certified for mercury under NSF/ANSI 53. Several carbon pitchers in our catalog, including the Brita Elite, Brita Standard, PUR Plus, and ZeroWater pitchers, do carry an NSF/ANSI 53 mercury certification, so they earn credit in our scoring. A plain carbon pitcher certified only under NSF/ANSI 42 for taste and odor does not, and you should not assume mercury reduction from a general carbon claim. Check the model's certification listing for mercury by name.
Does boiling water remove mercury?
No. Boiling does not remove dissolved mercury and can concentrate it as water evaporates. Reducing mercury relies on certified treatment such as reverse osmosis under NSF/ANSI 58 or an activated-carbon filter certified for mercury under NSF/ANSI 53.

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