Water Reuse Handbook - the Public Building Commission of Chicago

Water Reuse Handbook
Tools and Strategies: Greywater System Design
Greywater System Design
Introduction
22 : Public Building Commission of Chicago
Greywater systems, although quickly growing in popularity around
the world, have been slower to catch on in the Chicagoland area.
This is likely due to the fact that this area gets adequate rainfall
for irrigation and even for toilet flushing, if desired, and greywater
systems are more complex and expensive than rainwater harvesting
systems. However, as water conservation pressures increase
internationally, and interest in environmental and water stewardship
rises, greywater may become a more widespread and viable option in
the Chicagoland area.
The basic strategy of a greywater system for interior building reuse
is to harvest greywater from appropriate sources (such as shower,
lavatory, and laundry water), filter and purify the water to an
acceptable water quality standard, and store it until needed to flush
toilets and/or urinals. Greywater reuse makes the most sense where
an adequate source water is present and available to be harvested.
For example, a public restroom with only includes a few sinks and
toilet/urinal fixtures and is likely not worth the expense of installing
a greywater system when a rainwater harvesting system would be a
better choice. Buildings that incorporate showers, such as fire stations
or residential buildings, are good candidates for greywater systems
as the water from one shower is approximately equal to one person’s
flushing needs for a day. See Planning for a Greywater System for
more information on choosing the proper system.
This section provides a series of recommendations for the components
believed to be needed for a greywater system to protect public safety.
The components included in the diagram on the previous page,
Sample Greywater System Diagram, are explained in greater detail
and more options for system components are given in the narrative
that follows.
Following the recommendations of this section does not guarantee
system permitting or approval from the City of Chicago or State of
Illinois. Rather, these design guidelines are meant to be used as a
starting point for the creation of a greywater system specific to the
project at hand.
System Design
City/State Review
& Approval
System
Installation
City/State
Inspection &
Approval
Testing &
Reporting
August 2011