Mike Merkle, John Logan (2003)   Scott Melbourne, Craig Skipton, Caroline Salisbury (2002)   Ayako Harada and Emily Rivers (2001)       Introduction   Greywater systems reuse non-fecal water for irrigation of landscape plants on a residential scale. The initial cost and installation of a Greywater System may be high, however over time the amount of water used and the amount of water returning to wastewater treatment facilities will diminish and reduce water bills. A Greywater system can be designed based on the layout of a site and the amount of users and their needs.       This is important because nitrogen is one of the hardest and most dangerous pollutants to remove from usable water supplies. As seen in Figure 2, the amounts of Nitrogen (N) are much greater in blackwater compared to greywater, the time and energy to remove N form the water becomes much greater, way then mix the two when only one type needs to be cleaned. Greywater as well contains far fewer pathogens then blackwater. That is a direct result of the absence of human waste within greywater. As well the small amounts of organic material that are in greywater decompose far faster than the amounts that are in blackwater, and the BOD is far less in greywater. This creates a situation where greywater can be cleaned and filtered faster and with less effort than black water (Figure3). In the face of these facts it is now seen that greywater can be used and recycled for other uses. Greywater systems as a whole can help to create a more sustainable life and return water and nutrients to the environment.       The sources of greywater are varied. But they all fall into one of two categories: recycled or reclaimed. Recycled water refers to water that has already been used by humans and has been kept free of contamination from blackwater sources. Some examples of recycled water are bath water, bathroom sink water, some kitchen water, and washing machine water. Reclaimed water refers to the captureing of new water that has not yet been used by humans.       The most common type of water reclamation is the collecting of rainwater for human use. The following discussion will focus on the application, components involved, and case studies of systems for both of these sources of greywater.