How to Read Specific NSF/ANSI 53 Reduction Claims

On an NSF/ANSI 53 listing, each health-related claim is tied to one row, and the row for the product you are buying is the one that tells you what it was certified to reduce. Each row ties one model and its replacement element to a service cycle in gallons, a flow rate, and the exact health-related contaminants the certifier accepted. Multipure's record shows how much that matters within a single brand. On November 3, 2026, its Aqualite (element CB5, 450 gallons at 0.5 gpm) listed lead, cyst and VOC reduction with no PFOA or PFOS claim, while its Aquaperform (element CB11As, 600 gallons at 1 gpm) added pentavalent arsenic, microcystin, PFOA and PFOS.

Both carry the same standard number, and both are certified for what their rows name. The rows simply name different things, and a household with a PFOA result in its water test would only find that claim on one of them.

Reading One Row of Multipure's 53 Record

The Multipure listing in NSF's health-effects directory lists seven models in the "Plumbed-In to Separate Tap" category. Here is the Aquaperform row, field by field.

The element column deserves as much attention as the model name, because the claims belong to the combination on the row: Aquaperform with CB11As. The service cycle and flow rate are part of the claim as well, a point the section on capacity returns to below.

Same Brand, Different Claim Lists

All seven Multipure rows share ten claims: asbestos, chlordane, cyst, lead, MTBE, mercury, PCB, toxaphene, turbidity and VOC reduction. What separates them is everything else on the row.

Source: NSF listing for Multipure, read November 3, 2026. Every service-cycle figure carries note (1) on the record.

The pattern is easy to see once the rows sit together. The model with the largest service cycle, Aquaversa at 750 gallons, has no PFAS claim, and the models with PFOA and PFOS claims span 340 to 600 gallons. Capacity and claim breadth are separate properties of a row, and neither predicts the other. The older roundup of brands with NSF/ANSI 53 listings is a good place to see which companies hold the standard; a table like this one is how to tell their models apart.

Footnotes That Change What a Claim Means

The VOC claim is the broadest line on Multipure's rows, and its footnote explains why. On the record, a VOC reduction claim "means the system reduces the concentration of all of the following contaminants," followed by a list of more than fifty entries that includes atrazine, benzene, several pesticides and herbicides, and "total trihalomethanes, which are a by-product of chlorination." A household whose water report flags trihalomethanes can read the VOC line as covering them.

Four other notes on the same page narrow claims instead of widening them. The single asterisk limits arsenic: the product "is intended for use only on water supplies that have been shown to be at or below the referenced concentration and valency of arsenic," here pentavalent arsenic at 50 ppb or less. Note [4] reads "PFOA/PFOS reduction claim evaluated to the 2021 version of NSF/ANSI Standard 53," which dates the test method. Note (1), "Claims of capacity or rated service cycle are not applicable for mechanical filtration," limits what the gallon figure applies to: it does not govern claims achieved by mechanical filtration. And note [3], "Suffix I = Unit has no hardware; appropriate for in line installation," tells a buyer that an "I" version of the Aquaperform or Aquaversa is the listed unit without hardware, intended for in-line installation. The "[Pb]" on these rows is a materials note: the product was "determined to possess weighted average lead content of <=0.25%" and meets the "lead free" plumbing requirements, which is separate from the lead-reduction claim in the claims column.

How to Word a Claim the Record Does Not Show

Reading listings carefully also means describing them carefully. The Aqualite row lists lead and VOC reduction and no PFOA or PFOS claim. The accurate description is "certified to NSF/ANSI 53 for lead, VOC and the other listed claims." Calling it "PFAS-certified" overstates the row, and saying "it does not remove PFAS" goes beyond the row in the other direction, since the record speaks only to what was certified.

The same discipline applies to the standard number. "Certified to NSF/ANSI 53" describes every row on the page, from Aquamini to Aqualuxe, so it carries no information about any one contaminant. A useful description always pairs the standard with the claim and the model: "Aquaperform with CB11As, NSF/ANSI 53, PFOA and PFOS reduction, 600 gallons."

Turning Service Cycle and Flow Into Household Numbers

NSF/ANSI 53 tests health claims more strictly than the aesthetic standard. Rick Andrew of NSF wrote in WC&P that its "higher level of conservatism" shows up in "flowrate, end point, contaminant concentration in the challenge water and required reduction of the contaminant," and that 53 "includes requirements for performance indication devices (PIDs) that inform users when replaceable treatment elements are due to be changed." NSF's own lead-reduction listings page puts the household side plainly: filters "must be replaced according to the manufacturer's recommended filter capacity so they can continue to reduce lead and other contaminants for which they are certified."

The service cycle turns into an estimated number of days of use once daily use is known. Measuring that is simple: fill a marked pitcher from the filtered tap for every glass, kettle and pot for a few typical days and average the total. The table below uses an example household that draws 2.5 gallons a day.

Example usage only; months use 30.4 days. Dividing the service cycle by a household's own measured daily use gives its estimate of how long the cartridge takes to reach its rated capacity.

Flow is the other number on the row. It is listed beside the claims for each model, from 0.5 gpm on the Aqualite and Aquamini to 1 gpm on the Aquaperform, and it is the figure that describes how quickly each listed configuration delivers water.

Filter Life You Can See on an Under-Sink RO

A smart under-sink RO system shows cartridge status at the tap, so the arithmetic above stays in the background. On the Viomi M1, a tankless nine-stage RO system, the HD touchscreen faucet shows filter life next to live TDS readings. The Viomi app adds a record of water usage and sends a reminder when a cartridge is due, which keeps the replacement schedule in view without a notebook. Its two cartridges also have long service lives, up to two years for the PCB filter and up to four for the RO filter.

For households that start with a water test, a guide to testing tap water for lead explains how to get a result worth matching against a claim.

Frequently Asked Questions

What does the VOC claim actually cover?

On NSF 53 records, a VOC claim means the system reduces every chemical on the footnoted list, which runs to more than fifty entries, including trihalomethanes from chlorination and several pesticides and solvents. It is one line on the row that stands for the whole list.

Why is the service cycle shown with "(1)" on some rows?

Note (1) says capacity claims "are not applicable for mechanical filtration." On Multipure's record every service-cycle figure carries the note, which tells a reader that the gallon figure does not apply to claims achieved by mechanical filtration.

What does "evaluated to the 2021 version" mean for a PFOA and PFOS claim?

It names the edition of NSF/ANSI 53 used to test those two compounds. When two products both list PFOA and PFOS, the note tells you which edition of the method stands behind each claim.

Does a higher flow rate make a filter better?

A higher listed flow describes a faster-delivering configuration. It says nothing about which contaminants are covered, so flow is best compared only among rows that already list the claims you need.

Is the replacement element certified on its own?

On these records the element is listed as part of a system row, and the claims belong to that pairing. A cartridge that fits the same housing but carries a different code is not the element on the row.

Holding a 53 Row Up to Your Own Water Use

A 53 listing becomes useful when it is read against a household's own numbers. The contaminant in your water test has to appear on the row, with its footnotes read for any limit on form or concentration. The element code on the row is the cartridge to buy now and later. The service cycle, divided by measured daily use, gives an estimate of how long the cartridge takes to reach its rated capacity, and the flow rate is the rated delivery listed for that configuration. Read that way, a standard number becomes a specific statement about one model, one cartridge and one set of contaminants.