*
s
Optional Water Efficiency Measure: May contribute to the 30 percent water efficiency requirement,
depending on the chosen WaterSense® Approved Certification Method (WACM).
UNDERSTAND
Single-family residences typically have a single meter that is required by
the water utility or authority having jurisdiction (AHJ) for billing purposes.
However, this is not always the case. It is common for homes supplied
with onsite well water to not have a meter installed.
WaterSense encourages installation of water meters, even when not
required by the local water utility or AHJ, to help homeowners and
multifamily building managers understand and manage their water use.
Multifamily properties typically have a master meter for a
whole building or property, unless submetering of individual
units is required by the water utility or AHJ, or unless the
property plans to submeter each unit for billing purposes.
Individual metering or submetering for each unit in
multifamily buildings helps residents track their usage and
allows property managers to identify and manage issues
such as leaks in a specific unit.
Utility water meters are typically owned by the water utility
and are used to track water use from whole properties or
significant pieces of a property. To be separately metered,
each unit must represent a wholly separate plumbing system
attached to the main line. Submetering typically involves
using downstream meters to monitor distinct uses of water
or systems.
Work with the water utility or AHJ to identify the meter type
and size appropriate for the home or unit. Pursue reducing
the meter size to the extent possible, which often reduces
initial and ongoing charges from the utility. If a multifamily
building is pursuing submetering independent of a water
utility, it is important to select the correct type and size of
meter.
For multifamily buildings, meters and submeters can be
integrated into a centralized building management or billing
system, making it easy to track water usage and accurately
bill residents.
A dedicated irrigation meter might be appropriate for some
types of residential properties, such as single-family
residences with large landscapes, multifamily buildings,
homeowners associations with outdoor common space, or
Understand Local
Submetering Rules
Owners and operators of multifamily
properties should be sure to
understand the rules and regulations
related to submetering and resident
utility billing, as these can vary by
location. For example, some states or
local utilities may require the use of
submeters for individual units, whereas
other states require prior approval from
the responsible state agency or public
utilities commission before installing
submeters.
While WaterSense recommends water
metering and submetering wherever
feasible, another common strategy to
recoup water costs is through a Ratio
Utility Billing System (RUBS). Through a
RUBS program, a property owner is
able to allocate costs from a master
meter serving a multifamily property to
individual units, typically based on
square footage, occupancy, and/or
other factors.
To find out more regulations pertaining
to submetering or RUBS, contact your
state government, public utility
commission, or water utility.

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properties with access to reclaimed water for irrigation
purposes. These meters exclusively measure outdoor water
use and can be particularly helpful for evaluating outdoor
water efficiency.
BUILD
•	INVESTIGATE submetering during the early stages of
designing the plumbing system for multifamily properties.
Consider supplying each unit with a single pipe source for the
water to facilitate individual unit submetering, which is less
expensive than metering each source of water entering the
unit.
•	SELECT equipment that is best suited for the property. For
example, positive displacement meters may be well-suited
for residential applications, because they have high accuracy
at low flows and can precisely measure peak flows.
•	COMMUNICATE with the water utility or meter manufacturer
to select an appropriately sized meter, which depends on the
home's or unit's size, function, fixture types, anticipated
occupancy, and peak population. These statistics affect
minimum and maximum flow rates, which guide meter sizing.
•	FOLLOW the meter manufacturer's instructions for
installation.
•	INSTALL meters in an accessible location that is protected
from weather and potential damage (work with water utility as
appropriate).
•	AVOID installing the meter near pipe bends. Place the meter
where there is a length of straight pipe equivalent to at least
10 times the pipe diameter downstream of the meter and five
times the pipe diameter upstream of the meter.
•	INCLUDE a strainer on all meters and submeters to prevent
debris and sediment from damaging the device. An inline
strainer on the meter's inlet will prevent debris and sediment
from entering the meter body.
_EJ VERIFY
•	REVIEW building plans to identify water meter location(s).
•	CONFIRM that a meter or alternative for tracking water use is
installed for each unit in a multifamily building.
•	ENSURE that residents can easily access information from
the submeters.
*NOTE: Consult with the Home Certification Organization for
specific verification protocols.
Savings Potential
One national study on submetering of
multifamily buildings showed that
residents in submetered units used
approximately 15 percent less water
than residents in unmetered units.
Learn More
•	EPA's WaterSense at Work: Best
Management Practices at
www.epa.gov/watersense/best-
management-practices guide has
information on implementing
metering in commercial and
institutional properties, but much
of the information is also relevant
to multifamily buildings. Builders
and property managers may find
the document useful, especially
for tips on meter installation and
maintenance.
•	Pacific Northwest National
Laboratory's Water Metering Best
Practices guide at
www.pnnl.gov/publications/water
-metering-best-practices has
useful recommendations for
selecting a meter.
•	lAPMO's Water Demand
Calculator at
www, iapmo. o rg/wa te r-d e m a n d -
calculator/ can help right-size
plumbing systems based on
anticipated maximum flow rates.
This technical fact sheet is part of EPA's Technical Reference Manual for
WaterSense Labeled Homes. For the full document and other tools and	EPA-832-F-23-Q16
resources for homes, visit www.epa.gov/watersense/tools-and-resources.	July 2023

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