Greywater - Not a Black or White Issue

It seems easy, simple, and obvious. Water used while washing your hands could be caught and used to water a fruit tree. The tree doesn't need water treated at the local treatment plant. While it makes sense to try to reuse things when we can, greywater use is not so simple. The systems vary wildly in complexity and the dangers of contaminant exposure are very rare but also very real.

Here's a little quick reference comparison I worked up to help you compare collecting rain water in barrels and using a passive greywater system:

Rain Barrel Collection	Passive Greywater System
Especially helpful in times of drought	Especially helpful in times of drought
Hose directs water using gravity	Hose directs water using gravity
Not for human consumption but contact is safe	No contact with human, animal, or edible fruit/vegetables (Water)
Can collect too much water but overflow systems allow excess to flow like gutter system. (Bakacs)	Can produce excessive amounts of water and needs supervision (Water)
Can be stored fairly safely - screen to keep out bugs and add 1.5 cups bleach to 1 gallon of water (Bakacs)	Cannot be stored more than 24 hours or becomes black water (Curry)
Should be tested for ecoli but roof runoff safe level (Bakacs)	Cannot be used in a sprinkler system. Must avoid becoming airborne in case of contaminant content. (Water)
No changes to daily life necessary	Must adjust cleaning products, laundry detergent, and personal cleaning products. (Curry)
Apply to soil not to plant (Bakacs)	Apply to soil not to plant (Water)
Very simple. Requires no skill	Simple is best but can get very complex
Uses existing gutter system downspout	Set up is very site specific (Water)
Equipment $100 barrel	Equipment - $100-5,000 (Water)
No energy cost -uses gravity	Low to high energy cost - depending on need for pumps and filters
Mosquitos and other bugs - add 1.5 cups bleach to 1 gallon water (Bakacs)	Mosquitos and other bugs - treatment depends on the system (Water)

Regarding greywater systems specifically, I found that a company called Greywater Action and Art Ludwig's book "Create an Oasis with Grey Water" were both excellent sources of information. It's wise to keep in mind that any information on greywater use systems from a company is heavy on information that sells the product. Credit must be given to Greywater Action for being fair in mentioning the limitations of grey water use in the garden and touching on the risks of contaminants. While both sources agree that greywater use involves a level of understanding, Art Ludwig's all out seemingly exhaustive list of errors and misconceptions is far more helpful to a homeowner attempting a decision.  Both sources agree on emphasizing a simple system as best but Ludwig lends numbers to the reasoning when he explains that a "typical residential grey water system will save $5-$20 a worth of freshwater a month as best" which makes expensive systems not worth the effort.

It seems to me that grey water is much too complex to handle, store, and dispose of properly without adding the issue of building and maintaining a system over time. On the other hand, the rain barrel collection idea seems to build on the permaculture principles to plant where the water naturally settles, contour the earth to capture the water, and redirect water as it flows or falls.

Works Cited

Bakacs, Michele. "Rain Barrels Part IV: Testing and Applying Harvested Water to Irrigate a Vegetable Garden." Rutgers: New Jersey Agricultural Experiment Station. Rutgers, Dec. 2013. Web. 13 Mar. 2016.

Ludwig, Art. Create an Oasis with Greywater : Your Complete Guide to Choosing, Building, and Using Greywater Systems. Santa Barbara, CA :Oasis Design, 2000. Print.

"About Greywater Reuse." Greywateraction.org. Greywater Action, n.d. Web. 13 Mar. 2016.