GRAY WATER
RECLAMATION SYSTEMS
Packaged systems are the new frontier of residential water conservation.
If you’re lIke many In the
industry, water conservation has
become a key element of your business. that means you commonly
find yourself specifying and installing water efficient toilets, faucets and
showerheads. you may even be installing efficient hot water delivery systems
that minimize the amount of water
wasted while waiting for hot water. at
the same time, the need for even more
water savings continues. Which may
leave you wondering: how will we produce homes that use even less water?
to be sure, product manufacturers
will continue to innovate and reduce
the water consumed by their products.
But as the water consumed by toilets,
faucets, showerheads and appliances
gets smaller and smaller, so will the
potential future savings. What is
needed are entirely new and innovative
sources of water savings. one approach
that is appearing on the horizon for
homes in the united States are graywater reclamation systems. These new,
self-contained appliances are nothing
less than miniature water-treatment
facilities that can be installed in the
basements, crawlspaces or garages of
homes. They work by diverting some
of the least contaminated wastewater,
known as graywater, from the sanitary sewer and treating it. That treated
water can then be used for a variety of
non-potable applications both inside
and outside of the home — instead of
potable water.
Currently, studies estimate that
only 7% of u.S. households are reusing any graywater1 onsite. to date,
state laws and regulations that vary
widely throughout the country have
limited use of graywater. few locales
allow treated graywater to be reused
indoors, and requirements for the
quality of the water slated for various uses differ significantly. that,
This Water Legacy system is about the size of a water heater.
standard nearing completion, nSf 350
onsite residential and Commercial
Graywater treatment Systems, will
provide a uniform water quality definition that can be used nationwide.
This opens the door for graywater reclamation systems to come into more
widespread use residentially in the
coming years.
however, is beginning to change, as
a result of continued urgent needs to
reduce potable water consumption,
new green codes and standards, and
improved technology.
new national green building codes,
standards and programs are calling for
graywater reuse to significantly reduce
potable water consumption, creating
a demand for the technologies and
regulations needed to support reuse.
for example, ICC’s new International
Green Construction Code (IgCC),
which is currently under development, contains a detailed section on
graywater reuse that expands on the
provisions in the International Plumbing Code (IPC). a new water quality
WHAT IS GRAYWATER?
Before getting into the reuse system
technologies, it’s important to have a
clear understanding of what graywater
is and, even more importantly, what it
is not. Graywater is not potable water,
nor is it sewage. In most cases, it lies
somewhere in between. most definitions regarding graywater center on its
sources. The IPC, for example, defines
graywater as, “Waste discharged from
lavatories, bathtubs, showers, clothes
washers and laundry trays.” notably
the list does not include water closets,
dishwashers or kitchen faucets. These
other discharges, which are known as
blackwater, are the most highly contaminated, and must be discharged to
the sanitary sewer or septic system.
It’s also important to understand
the distinction between treated and
untreated graywater. untreated graywater is collected from the sources
described and contains microorganisms
(some of which are likely pathogenic),
lint, hair, fats, sand, chemicals, soaps
and the like. treated graywater is provided by a reclamation system, and is
filtered and disinfected in accordance
with local requirements for the intended
application. It is still not potable, but
depending on the need and the system,
microorganism counts are dramatically
lower, most solids have been removed,
and the chemical properties have been
adjusted. While untreated graywater
is usually only suitable for subsurface
irrigation and groundwater recharge,
