How do I build a gray water purification system or can I purchase one?

Asked by larry
Eau Claire, WI

How do I build a gray water purification system or can I purchase one?



There are a variety of companies that manufacture gray water collection systems that allow you to use the recovered gray water (from showers/tubs, lavatory sinks, laundry rooms and kitchen sinks depending 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 the kitchen sink or dishwasher is available from Gray Water Systems. They offer a packaged system for $708 plus 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 box filter 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 be interested in this link showing an urban system used to support an urban lot food lot. This system has a constructed wetland to pre filter the water prior to distribution to and through the distribution 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 you can still realize a significant reduction in water use if you install a gray water system for landscape and toilet use.

Check with your local code official to make sure they allow any gray water recovery before you 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-certified home in Door, Michigan that has a gray water wetland, composting toilets and a 5000-gallon rainwater cistern and purification system that provides 100% of potable water needs.

Happy water savings!

The General



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?"


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