Rainwater harvesting is a technology used to collect, convey and store rain from relatively clean surfaces such as a roof for later use. This is water that would otherwise have gone down the drainage system or into the ground. The water is generally stored in a rainwater tank or directed into mechanisms that can recharge groundwater. Rainwater harvesting can provide water for human consumption, reduce water bills and lessen the need to build reservoirs which may require the use of valuable land.

Rainwater harvesting has been practiced for over 4,000 years throughout the world. It has provided drinking water, domestic water, water for livestock, water for small irrigation and a way to replenish ground water levels. Traditionally, rainwater harvesting has been practiced in arid and semiarid areas. It has become an integral part of societies in remote places where piping water and reliance on wells is not an option.

Rainwater harvesting in urban areas and cities can have diverse benefits. Providing supplemental water for the city’s requirements, increasing soil moisture levels for urban greenery, increasing the ground water table through artificial recharge, mitigating urban flooding and improving the quality of groundwater are a few of the many benefits. In homes and buildings, collected rainwater can be used for irrigation, flushing toilets and washing laundry. In hard water areas rainwater is superior to city water for non-potable use. With proper filtration and treatment, harvested rainwater can also be used for showering, bathing, or drinking.

Rainwater harvesting is also effective in reducing stormwater runoff pollution into the watershed. When rain falls, it is clean, but it immediately picks up pollutants from rooftops and pavement. This pollution is carried into storm drains and then into streams. Collecting stormwater from rooftops and directing it to storage tanks so it can be used in and around a building decreases the volume and rate of stormwater runoff thus protecting local bodies of water from pollution.

LEED™ / Green Building Design - A Green Idea
The LEED (Leadership in Energy and Environment Design) Green Building Rating System™ was devised as a voluntary, consensus-based national standard for developing high-performance, sustainable buildings. LEED was initially created by the U.S. Green Building Council (USGBC) to establish a common measurement to define “green building.” It has since grown into a program aimed at raising awareness of and promoting integrated “green” building projects.

How does a building become a “green” building? Through design and construction that concentrates on:
• Conserving water;
• Reducing energy consumption;
• Reducing the depletion of natural resources and materials;
• Creating a sustainable site;
• Use of innovative design; and
• Improving indoor environmental quality.

To become LEED™ certified, the building is rated by these six categories. Within each category, points are awarded based on the LEED Green Building Rating System™.

LEED™ awards points to building designs for a variety of energy-efficient and environmentally friendly features, from the installation of radiant heating to reduction of energy consumption, to grey water recycling, to the use of local building materials that require less energy to transport.

The green building movement is an essential part of the solution to the energy, resource, and climate issues our country faces. In the United States, buildings annually account for 39% of the U.S. primary energy use; 70% of the U.S. resource consumption; consume 40% of raw materials globally; and use 12.2% of all potable water, or 15 trillion gallons per year.

LEED™ points are not given to individual products, but to an aggregate of the building system that saves water, energy, and contributes to a healthy indoor environment.

On average, a LEED™ certified building uses 30% less water than a conventional building, which translates to more than 1 million gallons of water saved per year. Reducing the amount of water that needs to be conveyed to and treated by municipal wastewater treatment facilities also reduces pumping and process energy required to these systems. LEED™, through practices like rainwater harvesting, promotes on-site storage and use of rainwater to lower water consumption cost, and it reduces the impact on storm drainage and municipal treatment systems.

In general, Certified and Silver LEED® projects tend to achieve the first irrigation and water use reduction point, using standard technologies at no additional cost. Gold and Platinum projects tend to achieve all 5 water points, typically at reasonable added cost, but there is a commitment to using new technologies, products and methods such as Rainwater Harvesting.