I just installed a “laundry to landscape” greywater system at the house of Lora “Homegrown Neighbor” Hall using greywater guru Art Ludwig’s free open-source plans. It was a cinch. And, thanks to a revision in the California plumbing code last year, it’s legal with no permit required.
I started in the laundry room by rigging up a three way diverter valve so that Lora can route the greywater back to the sewer if it’s been raining too much or if she’s bleaching her Prada (not likey, by the way). The diverter, somewhat of an exotic plumbing part, was ordered off of Ludwig’s website. At $47 it was the most expensive part of the system, but it’s well built.
Next, I rigged up two check valves, essentially a one-way gate, one to prevent greywater from siphoning back into the washing machine and another to act as a vent. You could also just use a six foot section of pipe as a vent, but Lora’s overhanging roof made that impossible.
The most labor intensive part of the process was digging the trench for the pipe out in the garden. Lora decided how many outlets she wanted in the garden and we consulted the “calculator” on Ludwig’s site (more of a chart than a calculator, actually, since he’s done the math for you). The calculator basically gives a range of outlet sizes and numbers so that you can get an even flow to the outlets but not risk burning out the washing machine’s pump. With nine outlets Ludwig suggests a 3/8-inch hole. We simply drilled 3/8-inch holes in the bottom of the PVC pipe that we ran out into the garden. The outlets flow into mini-mulch basins along the side of some perennial shrubs and a few small fruit trees.
Altogether it took just a few hours. Lora ran a load of clothes immediately and it worked perfectly. It was one of the easiest home improvement projects I’ve done. No cursing whatsoever! Now Lora can’t wait to do the laundry. She, of course, uses only Oasis Biocompatible Laundry Detergent. Note that many “eco” detergents will kill terrestrial plants–I’ll do a blog post on this shortly, as I discovered one major manufacturer claiming that a detergent was safe for greywater only to discover that it contained several different sodium compounds, definitely bad for soil!
Ludwig gives both a version of this project in PVC and another in HDPE plastic. I chose to work with the politically incorrect PVC since I couldn’t find the groovier 1-inch HDPE in less than 300 foot rolls. If any of you know of a source where you can get 1-inch HDPE by the foot, please let me know in the comments.
If you’d like to do this yourself the plans are all on Ludwigs site under Laundry to Landscape. In addition to the plans there is a parts list for both the PVC and HDPE versions and the aforementioned calculator. If you don’t think you can do it yourself (remember it’s easy!) you could conceivably hand the plans to a handyman. A plumber would be too expensive, in my opinion.
See also Ludwig’s book The New Create an Oasis with Greywater.