Greywater Design and Installation Workshop

almaden reservoir car

Learn how to install the popular “laundry to landscape” (L2L) greywater system in this design workshop presented by Laura Allen of Greywater Action and Leigh Jerrard of Greywater Corps.

Laundry to landscape greywater systems are simple, affordable, and easy to maintain. With your own L2L system you can irrigate your landscape each time you do laundry, saving you water, time, and resources. Experienced instructors will lead you step-by-step through the design process, tailoring a system to fit your home. This system is legal to install without a permit, just follow 12 basic guidelines you’ll learn about in class.


  • How to design a system for your home and landscape
  • How to build a system- you’ll create a “mock-up” of a real system with real greywater parts
  • What parts you’ll need for your home
  • How much greywater you produce and how many plants you can water
  • What soaps and detergents are “greywater friendly”


  • Real L2L greywater system
  • Gravity “branched drain” greywater system from sinks

Date: February 22, 2014 – 10:00am to 12:30pm
Location: Los Angeles EcoVillage 117 Bimini Place LA, CA 90004
Cost: Sliding scale $15 to $40, limited work trade positions available

Register HERE

Bring: Photographs of your laundry room and landscape. Site plan of your yard.
For more information on an L2L system refer to the SF Graywater Guide for Outdoor Irrigation, downloadable HERE

Please join our mailing list to be notified of upcoming workshops.
A long-submerged abandoned car is exposed at the bottom of the now-dry Almaden Reservoir
(January 16, 2014. Photo: Michael Short, The Chronicle)

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  1. After your post about the somewhat hard-to-find soap options for laundry, I was thinking that shower-to-landscape would be easier. What are your thoughts?

    • It depends. If your shower plumbing is easily accessible you can just run the drain out to the garden. In our case it’s just not possible for a number of reasons–hillside, concrete, difficult to access waste line etc. Also, shower to landscape depends on gravity 1/4 inch per foot down–laundry machines have a pump, making the run out to the garden potentially easier. But again, it depends on your situation. A three way valve for the shower line is a good idea so you can send it back to the sewer if you live where it freezes or rains a lot. You can actually get a remote controlled valve for this purpose.

    • As Erik says, sometimes shower to landscape is more difficult, depending on geography. The washer is the most popular option because the pump makes everything easier. And don’t be put off by the special soaps! I just amended my post with a reader rec — a detergent called Ecos which is apparently sold in Whole Foods.

      If you’re considering different greywater systems, you might want to check out Create an Oasis with Greywater by Art Ludwig.

    • Margie–we are not running this event you will have to check with the organizers on their website.

  2. Thinking about greywater in light of your post, I checked my detergent. Of the six ingredients in ALL, four had “sodium” in the name of the ingredient. I did not check the percentage of each in the detergent.

    Since I use only a tsp or two tsp, how much salt can be put on the yard without affecting it adversely? I guess any is too much, but I suppose I am hoping. My washer is on an outside wall, so this would be a snap.

    Could I decide to only use the washer to collect water in a barrel and then use the barrel to water my container garden? After I got water for the container garden, then I could send most of the wash water to the sewer. Or, am I asking for trouble?

    Another water question: I use the water I collect from two window ACs for watering food plants in the yard. I also use water from the dehumidifier for food plants. Both are free. Plus, it has no fluoride or any elements from the water treatment plant, no medicines dumped into the city water. Is water that drips from the window AC and dehumidifier harmful to food plants?

    • Hmmm. These are some difficult questions!

      Generally speaking, I’d avoid placing any salt at all in my soil. However, the more water a location gets, the more readily the salts will wash through, so it is possible that a small amount of salt will not harm anything if there is sufficient water to counterbalance it. Still, I’d err on the side of caution. Why not use a detergent made for greywater instead of trying to make do with what you have?

      Regarding keeping your wash water around for container plants — one of the basic laws of greywater is that it must go directly to the landscape. The small amounts of organic matter present in wash water or shower water create a bacterial stew when left sitting. Believe me, even one day of sitting around results in some nasty, stinky water. Therefore all the water you save, by whatever means, should be distributed around the garden asap.

      Regarding your AC and dehumidifier water–that question is even more of a puzzler. We don’t have any such sources for water, and so no direct experience with it. The one thing that comes to mind when I consider the question is Legionnaire’s Disease, which arises from bacterial contamination of water in things like AC systems. I believe it can transmit both through the air and the soil. You may want to read up on that before using those water sources.

  3. I use ALL because of allergies to most other brands or types of laundry detergents. Hmmm, I momentarily forgot about the pathogens in the water and potential problems on plants. I used the ac and dehumidifier water for about 6 years with no harm, but I will stop that. I had vague misgivings but could find no warnings. One ac does drip into a flower bed where I plant food next to the house.

    The only use then for greywater I have would be to water my oak with a hundred foot canopy. Last year, it got no water for 6 weeks. However, the oak has deep roots. That instance could possibly have weakened it to the point it will die. Sometimes, the weather systems forget this is a humid, subtropical climate.

    My friend told me he heard something about ac water should not be used for watering garden plants.

    Thanks for the answers.

  4. Hm. Are things really this serious?

    One of the big sodiums on labels might be sodium hydroxide, or lye, which is required to make soap. Without it, you don’t have soap. In fact, soap itself is a salt (chemistry-wise).

    So is all soap bad? Even my homemade soap, made only from oil and lye?

    • Yes indeed, as I said in my post, natural soaps and shampoos are fine for greywater. Your homemade soap would be just fine. (Good on you for making it, by the way! I love homemade soap.) The only soaps I’d really look askance at would be the anti-bacterial/anti-microbial types, since we don’t want to discourage bacteria and microbes in the soil.

      As for the salt question — well, I often wish I had a chemistry degree, or was a soil scientist. Or preferably both. This stuff is confusing. All I keep in mind is that the soil is alive, and I want everything which goes on it to be life affirming. I have to make best guesses as to what that is –and is not. This means peering at ingredients lists and looking stuff up on wikipedia and making guesses.

      And I have to make compromises anyway, such as watering the yard with chlorinated water, which really can’t be good for the soil life. It may even be worse than letting a bit of salt slip in with the greywater, for all I know.

      So we all have to juggle with what we’re given. Also, the right answers, such as they are, are enormously situation specific, so generalizing is always a problem.

      A gardener in a wet climate would not have to worry about salt build up in the soil as much as I do. That lucky gardener would have more leeway in her greywater, I think (though she’d also have slugs, too, so…ha!)

      But here, I have two trees in the yard suffering from salt burns right now, simply due to the native presence of salt in the soil. There hasn’t been enough rain over the past two winters to prevent it from gathering in the plant tissues. So in this set of circumstances, we have to be ultra-cautious regarding salts.

      In general, though, I believe salt caution is a good caution no matter where you live.

    • Art Ludwig also notes in his book that soaps and shampoos are heavily diluted in the shower–not in great enough quantities to worry about.

    • Since I use maybe two teaspoons of laundry detergent in a load of laundry, don’t do as much laundry as most people since there is only one of me I wonder how much harm I can do. We get lots of rain. Remember, my area is designated as a humid subtropical climate. And, water drains from my yard since I sit above the road and the neighbor behind. I do keep the makings for homemade laundry detergent, so I suppose I could use those ingredients for some of the clothes washing when I could divert water to the yard.

    • I wouldn’t do it. And homemade laundry detergents can still have salt in them. Better to be safe than sorry.

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