Water Conservation in Green Buildings
James Armstrong, CPE, CEM
There are several practical approaches to conserving water, including reducing the quantity used—by such measures as low-flow plumbing fixtures, and by landscaping approaches including xeriscaping and drip- and finely tuned-irrigation systems with rain sensors. Other methods include reuse of gray water for irrigation or HVAC systems; and collecting rainwater for similar uses, depending on the filtration methods.
A green building project should incorporate as many of these methods as possible.
Potable Water Reduction
The first line of defense in any green building project is conservation.
Therefore, any use of water must involve conservation equipment. These devices are required by code in many areas of the country. They include:
- Water-saving, low-flow shower heads and toilets.
- Water-saving or automatic shut-off sinks.
- Waterless urinals (using a chemical seal and highly polished surface to eliminate the need for flushing water).
- Recirculating dishwashers for commercial applications.
- Steam trap programs. (Since water is the basic component of steam, all steam trap programs inherently conserve water.) In commercial facilities that require steam for process, the steam condenses to become water. The percentage of water that is reused is a key component in water conservation.
Non-Potable Substitution Systems
These systems collect and use by-product water to replace potable water for various purposes.
Sources of substitution, reclaimed water include:
- Storm water systems: rainwater collected in tanks for non-potable water usage (can be used as potable water in some cases if properly filtered, in areas where air or other pollution does not create toxicity).
- Process water: can be recycled and collected for non-potable systems.
Some of the uses for non-potable reclaimed water include:
- Cooling systems heat sink
- Irrigation systems
- Toilet flushing
- Process cooling
This article is an excerpt from the book Green Building: Project Planning & Estimating which can be purchased through the RSMeans Bookstore.
This new 2nd edition has been completely updated with the latest in green building technologies, design concepts, standards, and costs. Includes Means’ Green Building CostWorks CD at no additional cost.
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