(I hope my cousin does not mind but I am posting one of our email correspondances here! Basically Cousin was interested in integrating a grey water re-use system into her home in Pennsylvania)
Her question:
Hi Cousin, I'm adding a bathroom to my house and asked my architect if i can have something installed to recycle the graywater from the bath/shower. I got a blank look!!!! then was told the local permitting process probably wouldn't permit it. When I was in Israel, my friend Yonit's shower drain led directly to her garden via a piece of exterior pvc pipe 
are homes in the Northeast ever designed to recycle graywater? are there resources for my builder/architect to come up to speed on it if so?
My Answer:
I love the idea of grey water re-use and so do my clients BUT my clients usually end up just collecting their rain water and recycling it into watering gardens etc. The reason is simply cost. The more you are using actual grey water (from shower, washer, etc) the more you get into costly plumbing and filter systems and the more maintenance. (There are actually health issues re: bacteria and our codes are likely more stringent than in Israel,etc. That said every county is different- talk to your local water/ health official. But yes it can be done and is done... sometimes)
first a couple of links:
http://www.smarterhomes.org.nz/water/re-using-greywater/
All of my clients so far have balked at the cost and opted for simple rain barrels or more elaborate rain water collection systems- gutters drain to underground holding tanks and go through light filtering, and are plumbed to the garden hoses or to an automated garden watering system...with overflow for the whole system to sewer or septic system. One step beyond this would be doing the plumbing to bring it to your toilet etc. This gets into minorly complicated plumbing because you have to be able to get water from your regular source as well as your water collection. Beyond this - potable water- is also possible with enough filters and plumbing. Just gets into $$$.
(Image from Stark Environmental- Thank you Michael.)
Ironically the water collection guy I have talked to the most about water systems is in PA.
Here is his info: Michael Stark, mstark@starkenvironmental.com, http://www.starkenvironmental.com/b-8-consultation.html
You may not be able to get into the second link without a password so I copied below. I DO NOT agree with 'Maritn' on this one - his claim - that saving water in places with plenty of water is a waste of time- I feel is in correct. We are all going to be in a water crisis soon enough and what we do actually effects the whole world...for real scientific reasons - not just good karma!
Green Building Advisor Link:
Grey water 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 SUN, 05/22/2011 - 10:47
Answers newest to oldest oldest to newest:
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, GBA ADVISOR Posted Sun, 05/22/2011 - 19:31 2.
Joseph, 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, GBA ADVISOR Posted Mon, 05/23/2011 - 04:53
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 Sun, 05/29/2011 - 19:31
