Water Sense

WaterSense® Draft Specification for Point-of-Use
Reverse Osmosis Systems

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WaterSense

WaterSense® Draft Specification
for Point-of-Use Reverse Osmosis Systems

WaterSense® Draft Specification for Point-of-Use Reverse

Osmosis Systems

1.0 Scope and Objective

This specification establishes the criteria for point-of-use reverse osmosis (RO) systems to earn
a label under the U.S. Environmental Protection Agency's (EPA's) WaterSense program. It
applies to point-of-use RO systems, as applicable under the NSF International/American
National Standard Institute (ANSI) 58 Reverse Osmosis Drinking Water Treatment Systems1
standard and further defined below. Based on the scope of NSF/ANSI 58 and applicable
definitions included in NSF/ANSI 330 Glossary of drinking water treatment unit terminology and
ASSE 1086 Performance Requirements for Reverse Osmosis Water Efficiency—Drinking
Water, EPA is defining this product category as follows:

•	Reverse osmosis system—A system that incorporates a water treatment process that
removes undesirable materials from water by using pressure to force the water
molecules through a semipermeable membrane.

•	Point-of-use reverse osmosis system—A plumbed-in or faucet-mounted RO system
used to treat the drinking and/or cooking water at a single tap or multiple taps, but not
used to treat the majority of water used for washing and flushing or other non-
consumption purposes at a building or facility. Any batch RO system or device not
connected to the plumbing system is considered a point-of-use RO system.

The specification does not apply to:

•	Components (e.g., replacement filters, membranes) that do not make up a complete RO
system.

•	Point-of-entry RO systems.

•	RO system add-on devices, accessories, or aftermarket companion products (e.g.,
permeate pump).

This specification is designed to promote sustainable, efficient water use and a high level of
user satisfaction with RO system performance.

2.0 General Requirements

2.1	Except as otherwise indicated in this specification, the RO system shall conform to
applicable requirements in NSF/ANSI 58, including the total dissolved solids (TDS)
reduction requirement.

2.2	The RO system shall be equipped with a shut-off device.

3.0 Water Efficiency Criteria

3.1 The recovery rating and efficiency rating (as applicable) of the system shall be
tested in accordance with the applicable procedures in NSF/ANSI 58 and shall
meet the following criteria:

1 References to this and other standards apply to the most current versions of those standards.

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EPA

WaterSense® Draft Specification
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WaterSense

3.1.1	For a system with a storage tank, the recovery rating and efficiency rating
shall be a minimum of 30 percent.

3.1.2	For a system without a storage tank, the recovery rating shall be a
minimum of 30 percent.

4.0 Performance Criteria

4.1 Membrane Life: The system shall be tested in accordance with the Membrane Life
Test for High Efficiency Membrane Systems procedures of ASSE 1086 and shall
meet the following criteria:

4.1.1	The percent TDS reduction shall be a minimum of 75 percent each day.

4.1.2	The flow rate shall not decrease by more than 50 percent of the Day 1
reading throughout the test.

4.1.3	The percent recovery, as calculated according to the ASSE 1086 testing
procedures, shall be on average a minimum of 30 percent. One tenth of
the sample readings may be less than 30 percent but no less than 23
percent. The final percent recovery measurement shall be at a minimum
of 30 percent.

4.2 Performance Claims: The manufacturer's performance (chemical reduction and
mechanical filtration) claims for the RO system shall be verified according to the
applicable criteria and requirements of NSF/ANSI 58.

5.0 Packaging and Documentation Requirements

5.1	The RO system shall conform to applicable instructions and information
requirements in NSF/ANSI 58 in addition to the requirements included in this
section.

5.2	The system's packaging and point-of-purchase documentation (e.g., specification

sheet) shall be marked with the following information and messaging:

5.2.1 For a system with a storage tank: "This system is certified to achieve a
XX% efficiency rating in the production of treated water. This means that
it will send Y.Y gallons of water down the drain for every gallon of treated
water it produces."

XX% is the system's efficiency rating in two- or three-digit resolution (e.g.,
30% or 30.0%) as verified by testing in accordance with NSF/ANSI 58;
and

Y.Y is the system's waste-to-product ratio expressed in at least two-digit
resolution (e.g., 2.3 gallons) and calculated based on:

Where:

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Waste-to-product ratio = Y.Y =	1

verified efficiency rating

5.2.2	For a system without a storage tank: "This system is certified to achieve a
XX% recovery rating in the production of treated water. This means that it
will send Y.Y gallons of water down the drain for every gallon of treated
water it produces."

Where:

XX% is the system's recovery rating in two- or three-digit resolution (e.g.,
30% or 30.0%) as verified by testing in accordance with NSF/ANSI 58;
and

Y.Y is the system's waste-to-product ratio expressed in at least two-digit
resolution (e.g., 2.3 gallons) and calculated based on:

Waste-to-product ratio = Y.Y =	—:		1

verified recovery rating

5.2.3	For all systems, include the NSF/ANSI 58 verified contaminant removal
rates for the following contaminants:

•	Arsenic (pentavalent) at a concentration of 300 parts per billion (ppb)

•	Chromium (hexavalent and trivalent)

•	Lead

•	Nitrate/nitrite

•	Perfluorooctanoic acid (PFOA)/perfluorooctane sulfonate (PFOS)

If the system does not have verified reduction claims for any of the above
contaminants, the packaging and documentation shall clearly indicate that
the product has not been certified to remove these contaminants.

5.2.4	The information required in Sections 5.2.1 through 5.2.3, as applicable,
shall be marked on packaging and other point-of-purchase documentation
in a manner consistent with the table below.

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epa	WaterSense® Draft Specification

WaterSense	for Point-of-Use Reverse Osmosis Systems

	Water Efficiency and Performance at a Glance	

	Water Use	

This system is certified to achieve a XX% [efficiency rating/recovery
rating] in the production of treated water. This means that it will send
Y.Y gallons of water down the drain for every gallon of treated water

it produces.	

Contaminant Removal

Contaminant

NSF 58 Minimum
Required
Reduction

Actual Reduction

Arsenic1

96.7%

% Removal/Not Tested

Chromium2

66.7%

% Removal/Not Tested

Lead

96.7%

% Removal/Not Tested

Nitrate/nitrite

66.7%

% Removal/Not Tested

PFOA/PFOS3

95.3%

% Removal/Not Tested

•	All contaminant removal claims listed above are verified through
NSF/ANSI 58 testing

•	Contaminants listed as "Not tested" have not been verified for
removal under NSF/ANSI 58

•	All contaminants reduced by this system are listed in the
performance data sheet

•	Not all contaminants listed may be present in the water	

1	Pentavalent, at a concentration of 300 parts per billion (ppb)

2	Hexavalent and trivalent

3	Perfluorooctanoic acid/perfluorooctane sulfonate	

5.3	If a system requires the use of components or companion products (e.g., a
permeate pump) to meet the requirements of this specification, all components
and/or companion products shall be packaged and sold along with the system.

5.4	The manufacturer shall specify in the system manual and/or maintenance
instructions replacement parts for all system components the consumer is expected
to replace during the life of the system (e.g., RO membrane, pre-filters, post-filters,
shutoff valve, storage tank) along with their recommended replacement
frequencies.

5.5	A system shall not be packaged, marked, nor provided with instructions directing
the user to an operational setting that would override the system's efficiency, as
established by this specification and verified through testing. Any instruction related
to the maintenance of the system shall direct the user on how to maintain the
system's efficiency.

6.0 Effective Date

This specification's effective date is [TBD],

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WaterSense® Draft Specification
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7.0 Future Specification Revisions

EPA reserves the right to revise this specification should technological and/or market changes
affect is usefulness to consumers, industry, or the environment. Revisions to the specification
shall be made following discussions with industry partners and other interested stakeholders.

8.0 Definitions

Definitions within NSF/ANSI 330 are included by reference.

Point-of-entry RO system: An RO system used to treat the water supply at the entry of a
building or facility for drinking and for washing, flushing, or other non-consumption use. A point-
of-entry RO system has a minimum initial clean-system flow rate of not less than 15 liters per
minute at 103 kilopascals pressure drop and 18 ± 5 °C water temperature (not less than 4.0
gallons per minute at 15 pounds per square inch gauge pressure drop and 65 ± 10 °F water
temperature).

Shut-off device: A device that prevents reject water from an RO system when the system is not
treating water.

Waste-to-product ratio: A ratio that expresses the number of gallons of water an RO system
wastes for every gallon of treated water it produces. Can be expressed as a full ratio (i.e., 2.3:1)
or a single value (e.g., 2.3).

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Appendix A: Requirements for WaterSense Labeling

The following requirements must be met for products to bear the WaterSense label.
1.0 WaterSense Partnership

The manufacturer of the product must have a signed partnership agreement in place with EPA.
2.0 Conformity Assessment

Conformance to this specification must be certified by a licensed certifying body accredited in
accordance with the WaterSense Product Certification System.

3.0 WaterSense Label Use

Per the WaterSense Program Mark Guidelines, for all products certified to meet this
specification, manufacturers must include the WaterSense label on product packaging and in
online and printed specification sheets. Manufacturers should also display the WaterSense label
in association with any labeled products listed on the organization's website.

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