That’s a pressing question these days in some western states where water is scarce and some people are trying to find creative ways to reduce their water consumption.
Meet gray water, that water that comes from the drains of bath tubs, showers and washing machines. It’s not full of hazardous waste products, but is not usable for drinking or cooking. How about flushing your toilets or water lawns with gray water?
A growing “gray water brigade” is finding creative home plumbing solutions to re-route gray water into other uses in their homes. Sometimes the modifications are quite simple to do, costing just a few hundred dollars.
But they rarely meet the building codes of the cities the gray water. Systems that have been put into use by contractors meeting local construction guidelines can cost as much as $7,000. In a recent story in the New York Times, a plumbing contractor admitted that he now encourages people interested in recycling grey water to find their own home remedies rather than fork out big bucks for a professional solution.
The same story gave a quick description of one such homemade system. A pipe running from the house deposits shower and sink water into an elevated bathtub in the yard that is filled with gravel and reeds. The roots of the plants begin filtering and absorbing contaminants. The water then flows into a lower tub, also containing a reed bed, before flowing into a still-lower tub of floating water hyacinths and small fish. The whole system cost about $100 and the final product is used to water flower beds at a California home. Chemical tests of the filtered done by the homeowner show a slightly high level of phosphorus, but nothing the plants can handle.
But other water experts share their concerns with gray water, including the risks of open pools of water becoming a mosquito breeding ground, the possible crossing of gray water lines with other plumbing that could contaminate clean water, or using gray water to irrigate plants that might be eaten raw.
Most states now have regulations about gray water usage. But proponents of gray water say those rules make the idea cost prohibitive.
So what should be done on the gray water front? Is it okay for people to play with gray water at their own risk? Are the health risks too great for this kind of experimentation? Share your thoughts here with other Science Buzz readers.