I was on the phone the other day having a conversation about greywater with a person enrolled in an entrepreneurial program. She asked me an excellent question: did having a greywater system cause me to use more water?
She was alluding to a concept known as induced demand. In other words, when you have more of something you use more. Buy a hybrid car and you end up driving more miles since you don’t pay as much for gas. Build a four lane highway instead of a two lane one and so many more people end up driving that you end up with worse gridlock.
I’d never thought of induced demand when it comes to greywater, but it’s a good point. Did I plant more fruit trees because I had a greywater system? Has this caused more water consumption in our current drought? Honestly, I think the answer is yes.
You could probably find induced demand between the lines of David Homgren’s permaculture principles. But perhaps we should insert a thirteenth principle: acknowledge induced demand and work to prevent it. Simply being aware of the phenomenon is a good first step in avoiding its pitfalls.
My original greywater system consisted of a tank and a hose to drag around to a bunch of trees. I’ve since simplified the system. It’s now just a pipe leading from the laundry machine to one tree that needs just about as much water as we do in laundry each week. My second system is more of a 1:1 match between the waste water and the demands of the landscape.
Have you encountered induced demand on your homesteading path? If so where and how?