Reusing Greywater – A Practical Bathroom Application

For every complex and troubling problem there is a simple answer; and it’s almost always wrong. With another drought (or phase of a continuing drought) pestering the homeowners of the region, reuse of greywater would seem to be a quick-and-easy fix. “Greywater,” by the way, is the wastewater produced by bathing, clothes-washing and other uses not connected to the disposal of human waste. The latter is designated as “blackwater” and is definitely not a candidate for easy reuse.

OK, we’ve got all this water that ought to be perfect for irrigating the lawn and garden, right?! Just plumb the system so that the greywater goes to a holding tank for outdoor use on the grass, flowers and veggies. Problem solved! Not quite. The simple solution falls apart because we are historically careless about what goes down the drain, many common bath- and clothes-cleaning products are not compatible with this application, and stored unfiltered greywater—in the best of cases—will become a stinky bio-soup in short order. Can’t you just treat it with a little bleach to kill the bugs? Ask someone with a home swimming pool how easy it is to keep the water swimmable, or ask your plants how keen they are to be irrigated with diluted bleach.

There is a practical reuse of greywater that, while it won’t generate surplus water for irrigation, will save on overall drinking-water use. Reuse the greywater to replace potable water that would otherwise be converted into blackwater. Shunt the greywater to provide flushing water for the home toilets. Not very glamorous but it could save around a third of your water consumption. Some filtration is still needed but there are readily available systems in the metro area with proven technology to make the switch.

Still want to use greywater for irrigation? There are mechanical filters that can convert greywater to potable or almost potable status. If you have enough land, you can set up a wetland bio-filter to naturally reprocess the waste water for irrigation—cattails and friendly microbes will capture most of the bad stuff so the downstream water would be good for crops. We are, however, not talking about a backyard “water feature.”

Bottom line! Look at water-saving by diverting greywater to power the toilets and put in a rain-capture barrel to supplement natural irrigation. The Clarkston Community Garden recently installed a 500-gallon unit—that would require a bit of cosmetic shrouding—but smaller home units will provide a water reserve without sticking out like a sore thumb. Conserve by selecting plants suitable for dry conditions, and use soil amendments that capture and release irrigation water over time. That brief, heavy rain recharges the tiny capsules in the lawn or garden, making better use of the unpredictable deluges.

Tune in to The Bob and RodMan Home Show every Saturday from
9 to 11 a.m. on 920 AM-WGKA to learn how to improve your house or apartment. RodMan is a certified home inspector, knows residential property appraisal and is a hands-on home renovator. Bob owned a roofing company, has reclaimed distressed properties for years and has Master Licenses as a plumber, electrician and HVAC mechanic. www.bobandrodman.com