There are a variety of companies that manufacture gray water collection systems that allow youto use the recovered gray water (from showers/tubs, lavatory sinks, laundry rooms and kitchen sinksdepending on local codes) for flushing toilets. Gray water can also be used for landscaping purposes.
Graywater systems available to buy
A manufactured gray water reuse system (for landscape use) that is not suitable for collection from thekitchen sink or dishwasher is available from Gray Water Systems. They offer a packaged system for $708plus shipping/handling. You can view this system here.
Tarten Plumbing in Birmingham, Michigan makes custom systems for harvesting and filtering gray water.
- I'm including a Google video (here) showing the system with explanation by the system designer.
- This sand boxfilter system can be scaled for home or commercial use.
If you are interested in a home built system for use in garden/landscape irrigation you might beinterested in this link showing an urban system used to support an urban lot food lot. Thissystem has a constructed wetland to pre filter the water prior to distribution to and through thedistribution lines.
Check your local code
I don't know of any jurisdictions that would allow you to use recycled gray water for potable use but youcan still realize a significant reduction in water use if you install a gray water system for landscape andtoilet use.
Check with your local code official to make sure they allow any gray water recovery beforeyou invest in a system.
Other ways to save water
Another way to reduce water use is to install low flow shower heads (1.5 GPM) and lavatory sinks'faucets (0.5 GPM).
Capturing rain water can also reduce landscape water use. There is a LEED-certifiedhome in Door, Michigan that has a gray water wetland, composting toilets and a 5000-gallon rainwatercistern and purification system that provides 100% of potable water needs.
Happy water savings!
For more information:
Read "We want to design a greywater system for bathrooms we're renovating. Can you help?" a Q&A answered by Jesse Terzi.
Also read Randy Potter's Q&A "Is it feasible to reuse greywater as irrigation water?"