Reusing Gray Water?


Homeowner installing gray water piping
Yesterday’s San Francisco Chronicle had an article about couples making green DIY changes to their homes. Among them was a couple, Alissa Hauser and Steve Brown, who spent “a Saturday afternoon routing gray water pipes from their laundry machine to their garden.”

Now, each time they run a load of dirty clothes, the excess H{-2}O runs through a filtering system that waters their apple, plum and lemon trees. “In many ways, environmentalism has become an expensive, consumer-driven effort,” Hauser, a director at a nonprofit, said. “But this kind of project proves environmentalism can be a money-saving lifestyle, too.”

The couple “spent $250 on materials for a project from which they’ll potentially save thousands of dollars.”
Fascinating. My water bill is going to be huge next year when I finish landscaping, so this appeals to me. I did a little research into gray water. Basically gray water is wastewater we use in showers, dishwashers, washing machines, etc. It makes up about 50%-80% of our water bill. (There’s also blackwater, the stuff in the sewer with toxic chemicals and feces in it–I have no interest in messing with that.) It sounds good to reuse this water since it makes up so much of what we use in the household and is relatively clean, at least compared to blackwater.
But can you safely dump gray water into your garden without any problems? From the sound of it, this San Francisco couple simply diverted the pipe from their washing machine into their garden. I’m not sure I like that. What about the chemicals in the soap? It seems like you could hurt the earth-and your garden–by picking a bad soap and dumping its chemicals into your lawn. And what about all the bacteria, feces (baby diapers, anyone?), and other dangers that are in this water? This is why a lot of cities want you to get a permit before recycling gray water–it could be a health risk.
However, there are gray water purification systems, and if they could be installed in a simple, cost-effective way without the hassle of expensive permits, recycling gray water could potentially save you a lot of money. Still, this site has a long list of precautions about gray water that kind of scare me. A sampling:

* Use gloves when cleaning greywater filters
* Wash your hands after contact with greywater
* Microorganisms on plants – Don’t apply untreated greywater onto lawns, or fruits and vegetables that are eaten raw (eg. strawberries, lettuce, carrots)
* Breathing of microorganisms – Don’t recycle untreated greywater with sprinklers. Droplets can evaporate leaving harmful microorganisms in the air where they can be breathed in

I’m fascinated with green systems–they appeal to the part of me that likes using resources to their fullest potential. My husband and I plan to go solar in the next year or two when cheaper, more efficient solar panels come on the market. But some things seem like too much trouble and risk to bother with. Gray water recycling sounds like one of them.

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