Recently I have been studying for the Leadership in Energy and Environmental Design (LEED) Green Associate exam. The LEED system has become a useful tool in the green building field.

It does not do the work of the design team, but rather sets goals and provides the framework for a green building project.  I believe that it has also helped to advance the use of sustainable practices by providing a recognized benchmark, which has market value.

The LEED Green Building Rating System is a point system based on the following categories: sustainable sites, water efficiency, energy and atmosphere, materials and resources, indoor environmental quality, innovation in design and regional priority.

There are 100 possible credit points in each of the first 5 categories.  Innovation in design and regional priority credits allow for up to 10 bonus points.  Based on how many points a project obtains, it will receive a certification, silver, gold or platinum status.

While studying I was particularly interested in the water efficiency category and decided to get a more detailed understanding of the LEED credits by re-reading the chapters on water conservation and supply and integrated water management in Sustainable Infrastructure: The Guide to Green Engineering and Design.

In this blog I write about the water efficiency credits for LEED certification, and in subsequent posts I will go into further detail about some of the strategies that LEED recommends.

The water efficiency category for LEED certification provides benchmarks to reduce water usage and provides suggestions to accomplish this, such as, using efficient plumbing fixtures, using graywater or captured rainwater for non-potable uses, applying xeriscape landscaping techniques and installing sub-metering devices.

The most environmentally and wallet friendly way to protect water resources is to simply reduce demand and conserve water.  LEED addresses this by suggesting low-flow faucets, showerheads, and toilets, dual flush toilets and waterless urinals.  The Bank of America headquarters in New York City, which achieved platinum certification in 2008, estimates saving 3.4 million gallons of water per year by using waterless urinals and 1.1 gallons per year with low-flow bathroom fixtures!

LEED also suggests decreasing water usage by using non-potable water.  Non-potable water is water that does not meet drinking water standards set by the Environmental Protection Agency (EPA), but can be used for purposes that do not come into human contact. Sources of non-potable water include captured rainwater, stormwater, and graywater.   Using non-potable water for irrigation purposes is the safest and easiest use, especially using sub-surface irrigation. However, it can also be used indoors for toilet flushing and process water (cooling towers, boilers, chillers and commercial kitchen use).

In addition to using non-potable water for irrigation applications, we can minimize water usage for landscaping by choosing native plants and applying xeriscaping.  Xeriscaping is a type of landscaping which emphasizes minimal water use, soil improvements, mulching and efficient irrigation.  Designers should also use efficient irrigation equipment; for example: sprinkler systems are only 65% efficient while drip systems are 90% efficient.

Lastly, LEED suggests installing sub-metering devices for indoor, outdoor and process uses.  Sub-metering is useful for monitoring water use, identifying leaks or problems, and tracking peak periods of water use.  Most sub-metering devices track cold, potable water use.

Strategies such as “use low-flow plumbing fixtures” or  “install sub-metering” are relatively self-explanatory and do not require much design engineering.  However, utilizing graywater, harvesting rainwater and treating wastewater can be much more intensive strategies.   To understand these techniques, I turned to Sustainable Infrastructure: The Guide to Green Engineering and Design. In upcoming posts I will describe these methods in more detail.

Posted in BLOG, Design, Education/Career, Water Resources | 1 Comment »

One Response to “Water Efficiency Series: Part 1- LEED Concepts and Strategies”

1. chamil Jayakody says:

   April 20, 2011 at 11:17 am

   Pls send me the material impacting water efficiency for below mentioned items

   Water closet(ltr per flush)
   Urinals (Ltr per flush)
   Shower Heads-Service areas (ltr per minutes)
   Shower heads-Chalets (Ltr per minutes)
   Faucets(Ltr per minutes)

   Reply