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From Grey to Green–Making the Best of Recycled Waste Water

By Christopher Marciello
Greywater is an interesting resource. It is ever present in our daily lives, yet very few people actually are aware of its existence. So let’s start at the beginning. What is greywater? It is any used water resulting from some sort of washing chore. The water in the washing machine, all that you see while doing the dishes, that wonderful warm scrub in the shower that serves as a reminder of your great fortune to be alive and served by our modern conveniences — that’s all grey water. What greywater is not is any water that has been in contact with fecal matter or has come out of your toilet.

With that introduction alone, you get an idea of how abundant a resource greywater actually is. In fact, it’s so abundant that it is somewhat mystifying why we as a society haven’t been using it, especially when available research shows pretty convincingly that our reserves of clean water are rapidly diminishing.

What is greywater used for? This really depends on what your overall aim would eventually be. For simplicity’s sake, I’ll break it down into two categories, horticultural and agricultural. Horticultural includes the usage of plant materials exclusively for an aesthetic aim. Agricultural includes the production of food stuffs — pretty simple — and to make it even simpler, from here on out I’ll refer to them as hort or ag.
Hort greywater is limited to what your state/local laws permit. We’ll get into it shortly, but greywater is a fantastic source for all of your hort needs. For ag use, the basic rule is this: if edible portions of a plant would come into contact with greywater or greywater soaked soil, then this is not appropriate usage. Everything else is a go. For example, your macadamia nut tree that is producing like gangbusters is a great place for greywater. But for those irregularly shaped red globs of sunlight-filled love known as strawberries, not so good. For them, we would use the rainwater we’ve been harvesting, which is something you can read about in this article. A very thirsty lawn that has not yet been converted into a space for food production is also a very good place for the utilization of greywater.
How to get access to greywater? As I said previously, it is an abundant resource that we produce on a daily basis, primarily from our sinks (think washing dishes) and our washing machine, a tremendously underutilized resource of greywater. The washing machine in the average home, even low usage machines, produce thousands of gallons of greywater in a year. Take a look at your machine’s usage per wash, an average of about 30 gallons a week. Then extrapolate that to monthly usage, then to yearly usage. That is a lot of water going right into the sewer system. It is a huge waste of resources, especially when you consider that only 20% of the water we use is from a local source. That means that a tremendous amount of energy is spent moving water (that otherwise would be going to another ecosystem or to a local destination) over a great distance and then single sourcing its usage. That distance involves machines, evaporation, water charges, infrastructure — the list goes on. Oh yeah, it hits your pockets as well. All of that water has a cost.
How to use greywater? Depending on your region, the usage of greywater has specific and sometimes rather stringent applications. This is where professionals are of great importance: they will be aware of all potential complications and appropriate usages. With this in mind, there are a couple of points for the usage of greywater that I should touch upon. As I mentioned earlier, greywater does not involve any contact with fecal matter. So, for those of us who have small children and are using cloth diapers, this makes our washing machines a place where we have to be more particular. Consult your professional greywater harvesting professional here. They will install a 3-valve system so that contaminated water can be diverted into the water processing cycle.

Now let’s return to using greywater:
1. Fruit and nut bearing trees love greywater. On my previous property we fed our 15 trees — a variety of citrus, nut and fruit bearers that produced rather vigorously — exclusively with greywater from the two houses on the property. In fact, our 1300-square-foot home and the other, a 1500-square-foot house, produced more than we could utilize.
2. With a slight caveate, vegetables and fruiting shrubs are also a great place for the greywater: as I stated previously, if the fruiting parts are in contact with greywater or greywater soaked soil, then do not use this resource. Otherwise, this is a great use for greywater, as it is rich in usable nutrients and microbial life that make for a rich soil structure. If this is the application you’re interested in, your greywater pro can help. In my experience, subsurface usage is perfectly appropriate for your fruits and veggies that will touch the ground.
3. Landscape irrigation is where greywater can be either the primary water source for the standard landscape design or a wonderful accompaniment to your sustainable landscape design. Greywater also can become the exclusive source of water in a standard landscape design, thus reducing the threat of depleting our natural water resources.
4. Lawn irrigation is a bit of a hot button issue for me, so I’ll do my best to not make that apparent. Greywater for your lawn is an excellent way to decrease water usage for plant forms that require a tremendous amount of water to look good because they are non-native and have developed over the centuries to suit moist and water logged soils with lots of shade for most of the day. How was that? Greywater, when set up by a pro, can feed a very hungry lawn very efficiently, using water from the spigot only to supplement.

If you use water from the spigot or a commercial irrigation system, don’t water after sunrise or before sunset. Just a note about plant physiology: because plants are in relaxation mode during the hottest parts of the day — like us — they try not to do anything. They do not uptake water, so it will be wasted. Some final notes on greywater, and a message from a local greywater and rainwater harvesting professional: greywater does not contain toxic elements, so when you decide to switch to a greywater system, you must use biodegradable components if you are not doing so already. Greywater should not sit for more than 24 hours without some source of processing because if it sits, it will be stinky. When done correctly, you should not ever know that you are using greywater.

Greywater is not used for spray based irrigation systems. It is most often filtered through a mulching process that, when installed correctly,
is very simple to set up. At my previous property, we did it a little more intricately. We fed the greywater into a mulch bed that sat on top of stones about 8-12 inches in size, which sat on top of much smaller aggregate that sat on top of sand. Below the sand, an underground piping system conducted the water to a storage pond, where it was further cleaned with Horsetail Reed and Water Hyacinth. We did this because we stored the water above ground to use later on our trees. This system is much more complicated than most people would need or desire.

Brooke Sarson, owner of a local greywater harvesting design company, H2O-me, has some very useful facts posted on her website which I think might elucidate the usefulness of setting up a greywater system. Only 20% of our water comes from a local source, with most of the 80% coming from distances up to 400 miles away. This then amounts to 20% of the state’s overall energy usage. The average home’s washing machine is an easily accessible source for greywater that requires very little work to set up. On average, the parts for a greywater system cost about $150.00 dollars (U.S.). Do the math we talked about earlier and price out that difference. Then think about the environmental impact you can make through wise use of a very finite resource. When a greywater system is set up, it is self-sufficient. Water is used in the house; it goes into the system; and the trees, shrubs, and plants do the rest with a highly rich source of nutrient- and microbial-active water.

An excellent and highly knowledgable local resource for greywater is Brooke Sarson of H2O-me. Also a teacher of permaculture design, she can be reached at www.h2o-me.com or brooke@h20-me.com. Christopher Marciello (that’s me) can be reached at QuantumGreenMan@gmail.com — the website is on the way. I’m available for any questions around greywater, gardening or plant loving in general. Greywateraction.org is a fantastic site to learn more about the subject. Oasisdesign.net offers more education as well as products for greywater systems. You can also go to Greywater.org for all your greywater educational and discussion needs.
Use less, conserve more and enjoy.

About Christopher Marciello

Christopher Marciello is a jedi farmer, permaculture activist, preserver of seeds and chicken whisperer. Christopher holds a permaculture design certification through the San Diego Sustainable Living Institute and has recently become a staff instructor for them. Christopher has been active throughout the county designing and installing edible food forests as well as setting up residential water and rainwater harvesting systems with his company, C2 Agriculture. He and his family are currently building an urban homestead in escondido, ca. where they cultivate multiple varieties of trees and share space with a wonderful mixed variety backyard flock.

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  1. Excellent article. I knew nothing about greywater before I read it; now I am somewhat literate on the topic.
    Well organized; easy to read.
    You (green mom), are awesome….

  2. Christine Cummings

    Great information – loved finding out something so simple to do to change my effect on the environment. Well presented and easily understood by a novice in local environment impact issues…

  3. Loved the article. I was just about to do some research myself on the process. The article provided the information I was seeking as well as some additional information I wasn’t aware of.

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