Renewable water resources come in many forms and water is also an environmentally friendly way to generate power.  Some types of renewable water energy technologies include hydroelectric, ocean energy (wave farms), salient gradient power and rain water harvesting.  There are also systems that can be incorporated into homes and buildings to collect and retain water, recycle water and conserve water.  Methods of conserving and utilizing renewable or recyclable water include: harvesting rainwater to be used for irrigation of landscaping, greywater (wastewater produced from baths, showers, washers, etc) used for irrigation, selection of appliances that use water (washers, dishwashers, etc)  and other building products (toilets, faucets, etc) that conserve water, devices that divert, capture or recirculate hot water, use of water-pervious materials (gravel, crushed stone, pervious paving blocks) used for external areas to minimize runoff and increase filtration, and more.  Providers in this section offer environmentally friendly products and services related to renewable water energy technologies, rainwater harvesting, water collection & retention, water recyclability, and water conservation.