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Graywater filtration system

I have a customer requesting the installation of a grey water filtration/recycling system. The customer lives in the DC area and has explained that these systems are common and considered "green" in application in the urban DC area. The home I will be building for the customer is in the rural mountains of West Virginia. There is no shortage of water up here we have received close to 35" this year to date and average about 60" a year.

We are looking to make budget decisions on "green" components. I admit I know little about these systems and have not talked to a plumber around here yet that doesn't say it is a waste of money. Is a grey water filtration/recycling system still "green" in an area that sees no water issues or will the system have a bigger footprint in terms of excess materials, maintenance, etc?

Asked by Joseph Garten
Posted May 22, 2011 11:47 AM ET
Edited Jan 16, 2013 9:45 AM ET


4 Answers

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You are probably better off using rainwater catchment over gray water. The water is much more pure, it needs minimal filtration and the entire system requires much less maintenance.

Health codes generally restrict gray water to use in toilets and underground irrigation, while rainwater can be used for almost any use, including potable water (with proper filtration) and spray irrigation. The cost per gallon for rainwater is significantly less than gray water in terms of both first cost and ongoing maintenance.

It may be appropriate to pipe the drains and toilet supplies for gray water even if you don't install the system initially. If higher performance gray water systems become available, then you can always install one, and having separate supply lines to toilets and laundry will allow you to use either rainwater or a future gray water system with minimal extra effort.

Answered by Carl Seville
Posted May 22, 2011 8:31 PM ET


Good green design and building doesn't follow a cookie-cutter checklist developed for a national audience. I agree with your implied criticism of greywater recycling systems for houses in high-rainfall areas: they don't make a lot of sense.

Each climate has its own challenges. Where I live in northern Vermont, for example, water is plentiful, but warm days are few. In this climate, a very good thermal envelope designed to retain heat is an important green feature. Features designed to save water are much less important.

Of course, in parts of Arizona or New Mexico, my priorities would be reversed.

Answered by Martin Holladay
Posted May 23, 2011 5:53 AM ET
Edited May 23, 2011 5:54 AM ET.


Thanks for responses. I was thinking along the same lines Martin. What I am really thinking though...how green can you be if your building an elaborate vacation home in a poor rural community? Things are getting pretty twisted....green washing.

Answered by Joseph Garten
Posted May 29, 2011 8:31 PM ET


A customer that's used to living on a municipal water/sewer system may be interested in grey water, but if they're going to have a well and a septic system at their new home, the water picture is completely different. A septic system deposits the waste water below grade where some of it finds its way back into the underground aquifer to be reused. I don't see any reason to use money, material, or energy to capture and reuse the water unless there is scarcity at the source, or you're obliged to discharge it in the wrong place.

Answered by David Meiland
Posted Jan 16, 2013 11:12 AM ET
Edited Jan 16, 2013 11:13 AM ET.

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