Water Metering

Seventy percent of the Earth’s surface is covered by water, but less than 1% of that water is fresh water. Only 1% of that 1% is accessible for human use.¹

According to the United Nations Environment Program, if our present patterns continue, two out of every three people will live in water-stressed conditions by the year 2025. A recent U.S. government survey showed at least 36 states expect to have local, regional, or statewide water shortages by 2013.

Each day roughly 340 billion gallons of fresh water are withdrawn from rivers, streams, and reservoirs. Sixty-five percent of the water consumed is discharged back into the water supplies after use.²

While the U.S. population doubled between 1950 and 2000, its water demand tripled.

Water efficiency helps protect our aquifers and the supply of renewable fresh water. The goals of the water efficiency credits are to

• reduce the quantity of water needed for a buildings and landscaping
• reduce municipal water use
• reduce the need for treatment of waste water

Reducing the quantity of water needed for a building and reducing the municipal water use go hand in hand. It is very unlikely that a building is not going to use any municipal water, so it is important to reduce the amount of water the building will use; this will often limit the use of municipal water. Potable water, which is water that is suitable for drinking, is one of the resources LEED is trying to conserve. Potable water comes from wells or municipal water systems. Non-potable water is not suitable for human consumption.

Water conservation strategies are typically no more expensive than traditional building methods. Buildings that use water efficiently can reduce operating costs through lower water use and sewage fees. For those strategies where the cost may be higher, the payback is usually quick. We’ll take a look at some of these strategies in this section.

For both energy efficiency and water efficiency LEED requires an efficiency first approach. After efficiency, then look for other ways to reduce use. For example with outdoor water irrigation if the design only calls for using rainwater irrigation, that doesn’t improve the efficiency of the irrigation system resulting in less water use. First design

the landscape to use less water, than look at ways to reuse water to further reduce demand.