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What Filter Removes

Which water filters remove nitrate?

3 of the 96 current water filters we track are certified to reduce nitrate (NSF/ANSI 58 listings). The lowest-priced is the AquaTru Carafe (countertop reverse osmosis, $375). Counting a year of replacement filters, the cheapest to own is the Aquasana SmartFlow RO ($801 the first year). 10 more claim it from brand-run lab tests only, which is not certification.

The EPA legal limit (MCL) for nitrate in public drinking water is 10 mg/L as N.

Source note

MCL and MCLG 10 mg/L. Nitrite (as N) separately MCL 1 mg/L. epa.gov

Lowest-priced certified filter, by type

Countertop reverse osmosis

AquaTru Carafe

$375 to buy · NSF/ANSI 58

Check price at AquaTru →

Under-sink reverse osmosis

Aquasana SmartFlow RO

$480 to buy · $321/yr for 2 · NSF/ANSI 58

Check price on Amazon →

Certified to reduce nitrate (3)

Each row is a certifier listing for this exact product with nitrate in its reduction claims; the listing is linked. Yearly cost is replacement filters (plus drain water for RO) for 2 people, from each brand's filter prices and ratings.

FilterTypeListingPriceFilters a year
AquaTru Carafe Countertop reverse osmosis IAPMO R&T, NSF/ANSI 58 $375 — Check price at AquaTru
AquaTru Classic Countertop reverse osmosis IAPMO R&T, NSF/ANSI 58 $475 — Check price on Amazon
Aquasana SmartFlow RO Under-sink reverse osmosis WQA, NSF/ANSI 58 $480 $321 Check price on Amazon

Brand tests only, not certified (10)

These brands cite a lab report for nitrate, but no certifier lists the claim for the product. A lab report can be real; it is not an independent, ongoing certification with factory audits.

No nitrate claim (83 filters)

Common questions

Which water filters remove nitrate?

3 of the 96 current water filters we track are certified to reduce nitrate (NSF/ANSI 58 listings). The lowest-priced is the AquaTru Carafe (countertop reverse osmosis, $375). Counting a year of replacement filters, the cheapest to own is the Aquasana SmartFlow RO ($801 the first year). 10 more claim it from brand-run lab tests only, which is not certification.

Is there a legal limit for nitrate in tap water?

The EPA legal limit (MCL) for nitrate in public drinking water is 10 mg/L as N. EPA WaterSense guide: carbon filtration does not remove nitrates. CDC: RO may reduce nitrate; distillation removes it. Mainly a private-well concern (EPA/CDC recommend annual nitrate tests for wells).

How do I know a filter really removes nitrate?

Look it up in the certifier's public database (NSF, WQA, IAPMO or CSA) under the exact model, and check that nitrate is in its list of reduction claims (usually under NSF/ANSI 58). "Tested to NSF standards" in an ad is not the same as a listing.