Graywater Uses and Benefits

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Graywater can replace tap water for non-potable water needs, such as irrigation, toilet flushing, clothes washing and numerous industrial processes. Matching water end use with the best water source is the way to go!


Outdoor Use


  • Landscape direct: Simple systems redirect graywater outside to irrigate the landscape. Common types include laundry-to-landscape and branched drain systems.
  • Drip irrigation: Graywater systems that filter out particulate matter can direct graywater into a special drip irrigation system. Some systems require the user to manually clean the filter, other more complex systems have automatic filter cleaning built in.

Usually designed by an engineering company, these systems filter graywater so it can pass through small emitters used in drip irrigation. Special graywater drip tubing is used. These systems are automated using timers to control irrigation zones. They are also plumbed to take in potable water when there is not enough graywater to irrigate, or to dump excess graywater into the sewer system if there is more graywater than irrigation need. Check our Waterwise Business Directory to find the people and equipment you need for the job.

Indoor Use


With the concept of integrated water management in mind, in many settings, it is much simpler to use graywater outside than to filter, disinfect, and pump it back inside the building. For most households, it is easier to use rainwater for toilet flushing and clothes washing. Small under-the-sink graywater units that can be used to flush toilets with bathroom sink water do exist, but technological and design improvements are yet needed. Industrial processes are a different case, and can be designed to reuse the water in-system.



Graywater is an important part of sustainable integrated water management because it can:

  • Reduce potable water use by 16 to 40 percent, depending on the house/site (Cohen 2009)
  • Reduce water bills
  • Reduce energy and chemicals used to treat the water to potable standards at the wastewater treatment plant
  • Reduce dependency on imported water or local aquifers
  • Encourage the use of nontoxic products
  • Connect people to their household water supply
  • Alleviate failing or overloaded septic systems or treatment plants
  • Provide drought insurance for your landscape