Greywater is water from your bathroom sinks, showers, tubs, and washing machines. It is not water that has come into contact with feces, either from the toilet or from washing diapers, which is called blackwater.
About 65 percent of domestic wastewater is greywater, and that translates into 40 gallons of water per person daily. For a family of four, that means about 5,000 gallons monthly – enough greywater fill a backyard swimming pool.
So being able to re-capture and re-cycle greywater means that the homeowner will save money on water bills, and there will be less pressure on the public sewage system too. And with California being an arid state, it’s necessary to preserve our precious water resources.
You can use greywater for toilet flushing and irrigation. Basically the setup of a greywater recycling system involves routing water from sinks, showers, and washing machines to a separate holding tank, rather than allowing it to go into the sewer system. It may be used directly for irrigation and toilet flushing, ideally after being passed through a sand or charcoal filter to remove big particles.
Simple low tech water systems could cost as low as $250, particularly if you are willing to do part of the labor yourself. It’s important to keep health and safety considerations in mind for the holding system, and to maintain it regularly.
California has fairly liberal laws for the installation of greywater systems by homeowners. Different cities have different policies, and you should certainly check the current policy in Oakland as the first thing to do before moving ahead. And in doing so, you will get good information about any on-going current incentives and rebates.
Sources: Using Greywater in the Landscape – What is Greywater Recycling?