Greywater FAQ

Frequently Asked Questions
about Greywater & Reuse

  • Why is greywater so important?

    Graywater reuse is an increasingly critical component for maintaining sustainable water supplies throughout the world, especially in drought prone regions.  Perhaps the Los Angeles Department of Water and Power web site stated it best: “graywater is necessary for the future of California. California’s water resources are limited as underscored by the recent drought. Further shortages would be devastating to the State and would severely impact growth, development and our quality of life. The future of California depends on water: Not only on finding additional resources but on reducing the demand. It has become necessary for the State to develop and exploit more water options to meet both current and future water demand. Greywater is one such additional resource. It provides a means to meet the need through recycling and reuse. Greywater reuse represents a means to achieve a sustainable future for California.”

  • How much water can the average household save reusing greywater?

    It is conservatively estimated that the GreenSmart Greywater Diverter can help enable households – as well as water districts – to reduce water consumption by 20% or more.  Depending on usage habits, this could mean a savings of approximately 4000 to 6000 gallons of water per month for a typical household of 4 people – which could add up to a savings of 48,000 to 72,000 gallons of water per year.

  • How much money can be saved?

    Cost savings are dependent on your local water rates and usage patterns.  Many water companies use a “Tiered” rate system where the price per gallon of water increases as you increase your usage — the more you use, the more it costs per gallon.

  • How much water is used during an average shower or bath?

    The average shower uses approximately 25 gallons of water per person.  The average bath uses 50 gallons of water.  One load of laundry can use about 25 gallons of water.

  • How much water is used for household landscape irrigation?

    Landscape irrigation uses anywhere from 32% (national average) to 70% (average in Southwest U.S.) of total residential water usage.

  • What exactly is “Greywater”?

    Greywater refers to untreated household wastewater that has not come into contact with sewage. Water that flows from showers, bathtubs, and clothes washing machines is considered greywater.  Greywater is NOT the water from toilets, dishwashers, kitchen sinks, or laundry water from soiled diapers.

  • Is Greywater Safe?

    A.  Greywater can safely be used with sub-surface or drip irrigation systems for gardens, plants and trees. There are some restrictions – you should not  apply directly to edible plants or spray greywater into the air.  Don’t store stagnant greywater for more than 24 hours in any type of holding tank.

    There are several greywater filtration systems currently on the market that provide filter tanks and high pressure pumps to assist in greywater irrigation.

  • When should greywater be directed to the sewer system?

    Divert greywater to the sewer when greywater contains large amounts of cleaning solvents or bleach, when using hair dye or other harsh chemicals, or for clothes washer waste from washing soiled diapers or greasy clothes.

  • How does reuse of greywater save energy?

    Every gallon of greywater used equates to less potable water that is used for irrigation purposes and less water that has to be pumped and treated. For instance, in California, a household using 50 gallons per day of greywater reduces energy demand by 108 kWh in a year.

  • What is a greywater Stub-out device?

    A greywater stub-out is the end of a drainage pipe that extends out from your home which is connected to your greywater sources.  The stub-out does not need to be operational at the time of installation as long as it is open (flow directed) to the sewer line. Once installed, the stub-out on the GreenSmart Diverter allows the greywater reuse option to be instituted at a later date.