Reuse Graywater for
Irrigation
Specify and
install wastewater plumbing piping to capture “graywater”
- drain water from baths, showers, laundry and bathroom sinks
- for sub-surface irrigation of outdoor landscaping. Graywater
piping should be labeled to distinguish it from other sanitary
piping.
A simple non-pumped
gravity system is appropriate if leaching chambers or box troughs
can be located downhill from the building, and maintenance staff
is available for regular inspections and filter changes.
Where maintenance
staff are not expected, pumped systems equipped with automatically
backwashed sand filters are most appropriate, though more expensive.
These systems, unlike other graywater systems, can be used for
drip irrigation of lawns and require minimal service.
- Ensure
graywater will not be exposed on the ground surface, even after
prolonged rain.
- Ensure
occupants are made aware of neglected maintenance or filter
changes by obvious signals such as a visible overflow.
- Post permanent
signage above sinks to ensure occupants use appropriate cleansers
and soaps.
Cautions
- Regular
inspection and maintenance are essential for non-automatic systems.
Post permanent documentation of maintenance procedures in the
building.
- Maintenance
of automatic systems should be handled by a service contract
with firms specializing in graywater systems.
- Mini leachfields
designed according to the California Plumbing Code have poor
irrigation performance. See Ludwig's publications for details.
