We are fortunate to live in a state that allows greywater recycling on a small scale. It is a great way to conserve water and offers some nice advantages. One can accurately predict the quantity a system will produce, plus it is rich in nutrients, which is great for landscaping.
Greywater is all water leaving the house that is not from the toilets or the kitchen. Greywater systems are simple and built on site with no controls and little filtration in new homes. In existing homes it can be more complex. Reusing greywater is an old technology that has been tried and used for decades. In New Mexico, you may recycle greywater on a landscape without a permit if you produce less than 250 gallons per day and install the system using published best practices (www.ose.state.nm.us/water-info/conservation/pdf-manuals/GreyWaterGuide-3Fnm-2006-09-12-op.pdf).