Free water. That's right. FREE WATER! The fact that we don't all use grey water to irrigate in dry climates is mind-blowing!
So what is grey water? Grey water (as opposed to Black water which is sewage) is the term used for the wastewater that comes from washing machines, sinks, showers and dishwashers. Averaging at a few hundred gallons per week this water can legally be used to irrigate your landscape. If you use biodegradable soaps and detergents all you need is some light organic filtration to use this water in your yard.
California has designated laundry-to-landscape systems for permit-free install. Which means that the 75-200 gallons of water that drains out of your washing machine every week could be irrigating most or all of your bushes and Trees!
If you're interested in DIY options and learning the basics of how these systems work, read on.
The gist is that you run a wide diameter hose from your washing machine's drain line directly out to your landscape but there's a few basic pointers you want to follow to ensure your system is both up to building code and problem free. Items that you may want to get professional plumbing help with are * for those of us who don't know how to cut PVC:
- *Install a diverter valve at the top of your washing machine's drain line so you can run water to sewage in emergency situations [i.e. if you need to do a bleach load (which could kill your plants) or if poop, blood or other unfriendly bodily outputs got on your clothes].
- Run 1 inch (or wider) tubing either parallel or uphill from your washing machine's drain line (near the top of the machine)
- *To prevent water getting sucked out of the machine when it is refilling install a vacuum breaker at the high point of the grey water line as near to the washer as possible.
- Dig pits 1-2' wide and 1' deep about a 2' foot distance from the base of large trees or shrubs you want to irrigate.
- You can run 10 branches off a laundry line or 15-20 drip omiters OR run the line to a soaker hose that weaves gently downhill in your landscape.
- Washing machine pumps are strong enough to move the water up to 100' away but can't handle much incline. Water can be distributed downhill at a potentially limitless distance.
- ALWAYS cover the places where your grey water comes out with mulch (the kind that breaks down, not rock or DG in this case). This is for both building code and ensuring maximum absorption of the grey water into the landscape.
Are you so pumped you are ready to get started and full DIY? Check out California's grey water originator Art Ludwig's page on installation basics. Despite plumbing jargon these systems really are beginner friendly. Here's a video of a complex laundry to landscape system install:
As my mentor Rob Avis used to say instead of using our resources wisely we're all "sh*tting in our drinking water and wiping our a** with old-growth forest." Choosing grey water is one BIG way to start reversing this phenomenon by both repurposing water that would otherwise get pumped into the ocean and replenishing local ground water stores.