Basic Sustainable Design
Principles
Energy
Efficiency
Material Efficiency
Water Efficiency
Regional Design
Water Efficiency
Sustainable design addresses the two largest
sources of water use in homes in order to reduce overall consumption of water:
In addition, sustainable design considers
opportunities to capture and reuse water.
Reducing water consumption benefits both the
resident—in terms of cost savings—and the environment. There are several environmental benefits of water
conservation. Conserving water helps ensure
that there will be adequate groundwater supplies for future generations, and preserves the
habitat values of surface water supplies. Reducing
water use also reduces requirements for wastewater treatment, which can be a significant
community expense, or individual homeowner expense in the case of septic systems.
Efficient Plumbing Fixtures
The largest single use of water in the average
American home is the toilet. However, new toilets are required to use 1.5 gallons or
less, a significant improvement over earlier models.
This water consumption can be eliminated with a
composting toilet, but such systems are
relatively uncommon due to their expense, space requirements, and consumer unfamiliarity
with alternative technologies. Other
household water consumption also can be reduced with water-conserving fixtures and
appliances, such as low-flow showerheads, faucet aerators, water-efficient dishwashers,
and clothes washers. Of course, occupant
behavior plays a significant role in water consumption, as well, so providing occupants
with pointers on water- conserving practices can reduce long-term water use.
Low-Demand Landscaping
Landscaping also consumes a significant amount of
water in American homes. Although landscaping water
use varies greatly by location and climate, incredible amounts of water are used
nationally to support conventional green lawns. There
are several ways to reduce landscaping water use. In
general, irrigation needs can be reduced by choosing plants native to the local area, or
known for their drought tolerance, thus reducing the supplementary water needs of the
landscape. The efficiency of water delivery
also can be improved. For example,
underground drip irrigation systems reduce water loss caused by evaporation of surface
water.
Water
Capture and Reuse
There are also opportunities to reduce household
water use by capturing waste water and using it again.
Some jurisdictions allow greywater systems to recover used household bath and
washwater for landscaping use. Stormwater is
another free water source. Many communities
are making significant efforts to control stormwater runoff that can cause erosion,
overwhelm water-treatment facilities, and contaminate surface water. Designing a neighborhood landscape that can
capture runoff and store stormwater for later irrigation use is one strategy. At the household level, rooftop water catchment
systems capture and store water. Catchment
systems can be complex enough to provide a household with drinking-quality water, or as
simple as a bucket placed under gutter downspouts to collect water for use on yard plants.
There are two principal means of improving water
efficiency in housing: reducing the water
demand of fixtures, appliances and landscaping; and reducing the loss of water in the form
of stormwater and evaporated irrigation water. Both
of these means achieve maximum efficiency when good occupant water conservation practices
are combined with efficient installed systems.
Next Section: Basic
Sustainable Design Principles: Regional Design
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