Working with greywater sources

Greywater is defined as water that has already been used in a household water supply that does not come from the toilet. (Toilet water is blackwater) Water from sinks, showers and washing machines qualify as greywater. It is too dirty for people and pets to drink but not too dirty for plants to drink as the plants are able to filter out the nasty from the water and just use the good stuff. A properly designed greywater system in essence, is a biological filter for your home’s wastewater.

Creating a greywater distribution system can be very simple. A bucket under a handwashing sink catches the draining water, at the end of the day you take the bucket out and dump the water onto a tree. That’s it! The concept relies entirely upon redirecting the greywater that would have otherwise ended up in a wastewater system onto a secondary source such as a shade tree, that can then add further value to a home.

But it does not stop there, the concept can be refined and elaborated upon to create a system that works time and time again without any additional user input and requires minimal maintenance. These are the systems that I design and install and it just takes a little more information from the basics to get there.

Construction of wetland for cleaning and distributing high amounts of laundry water
Construction of wetland for cleaning and distributing high amounts of laundry water

Important Safety Considerations

First off, greywater is only one step away from blackwater, ie. poo poo water, so we need to address and understand some health and saftey concerns and state regulations before beginning the design. Texas is not a highly regulated state but there are in fact, state regulations regarding the distribution of greywater, mostly regarding spetic tank sizing. That should tell you something right there about the importance of a correct design. The State of New Mexico also has some additional regulations that are worth reading as they are more specific about the actual practices of using the greywater.

An interesting point to note about Texas and New Mexico regulations is that a common source of greywater, the kitchen sink, is NOT allowed in greywater reuse systems. Think for a minute about everything that might end up in a kitchen sink like animal blood, grease and larger pieces of vegetables. What if you just did an oil change on your car and you need to wash up? Having the kitchen sink drain to the septic helps keep potentially toxic water out of the greywater system and out of the biological filter that you are building in your greywater treatment plan.

Pro Tip

If you are happy to DIY then I highly recommend to buy this book by Art Ludwig, there is no better resource with regards to greywater technology. Create an Oasis with Greywater
Most of my designs are based entirely upon or modified slightly from the concepts in this book and Art’s decades of experience in greywater systems. For immediate satisfaction you can browse the site to dig deeper into the information.

First things to consider

The following are expectation checks for Terlingua greywater systems just to get you started before you start designing.

  • Designs are best before construction begins. A newly conceived outdoor shower or washroom is an excellent candidate for greywater reuse. An existing fully plumbed in-slab system that drains to septic is not.
  • If you leave your homestead for several months at a time, create a backup plan for the plants that depend on your greywater system. This could mean a neighbor using your clothes washer or a system designed only for annuals.
  • Our soil is salty and alkaline and greywater irrigation increases the salinity by the addition of pee, sweat and soaps (yes you do pee in the shower and almost all “natural” cleaners contain sodium laurel sulfate) Soil quality will degrade over time without periodic flushing of salts or replacement of all soil, only conceivable in a containerized bed.
  • Grewater is best if it infiltrates the soil immediately, holding onto greywater by draining into a holding tank or letting it pool at the surface is not good practice.

Should you grow food with greywater?

The chance of contamination from greywater goes up the less water is filtered and the closer it comes to your mouth. The best practice is to leave greywater for growing shade, not food. You should balace your risk tolerance on a scale of 1-10.
1 (least risk) = using greywater for sub surface watering of landscape plants
10 (most risk) = directly pouring greywater on lettuce plants and not washing the leaves before fixing a salad.
Somewhere in between is using greywater for an edible fruit tree such as a pomegranate– you must be the judge and I will make no claim that I told you either or.

Garlic grown with pure rainwater only


Data compiled by the EPA indicates that, as a national average, landscape irrigation is by far the largest single use of water at both residential and commercial sites, using 59% and 35% of water, respectively (EPA, 2013) In hot climates, outdoor use ranges from 59%-67% compared to 22-38% in cooler climates (AWWA, 1999). There is no doubt that water is our most precious resource so if we can use rainwater and use it twice then we can achieve a much greater efficiency in our landscapes. Using greywater to water roots, which then grows to provide shade to our living areas just makes perfect sense.

Things you should know when developing a piece of land in South Brewster County

desert hills and scrub

You bought a tract of land in South Brewster County and you want to make it your home, your get away, your hunt camp, your oasis, where do you start? Start by observing the land, it will answer so many of your questions if you take the time to listen and observe. How does the land roll, what are the differences in elevation changes? Are the Mesquite trees taller than you and have a mature canopy or are they spread out wide and close to the ground? Is there any grass, where does it grow? Are there places that water pools, did you find any tracks in deep hardened mud? Are there completely bare areas with no vegetation at all? Ok, I could go on forever with this line of questioning but the point is to learn your property by observation, and you will learn more than anyone can tell you about things.

Likely the first thing you will want to do is to create some sort of shade if you don’t have any already. Observe the land, try to determine where the water runs when it does rain. That tall Mesquite tree looks wonderful to use as shade but there is a reason it is so tall. Thick stands of grass can only mean one thing, the rain may collect there and may NOT be the spot where you would want to build anything.

When you are ready to develop, don’t assume that anyone takes the land as seriously as you or I do. Bull dozers will scrape the land clean, bury your landscaping plants. Welders will lay metal on your bushes. The telephone company will drive over your creosotes. Plan for destruction and act before it happens. Walk, observe and transplant any valuable plants into pots or away from your build site before doing anything else. And if you don’t know what to do, please call me before any heavy equipment arrives on site. Too many rare, special, incredibly old or valuable plants are killed every year by land clearning.

Preventing erosion of newly formed land features is pretty important too. A new road cuts the land differently than before, a new flat cut bank on a house site needs further attention so the vegetation can grow back and hold the soil in place. The more extensive the erosion the more costly the repair so it is important to act as soon as you can to correct any problems.

At this homesite we applied a base layer of a geotextile ground grid anchored with rebar to the side of a newly buried septic tank.


The pockets in the ground grid were filled with a light growing medium and seeded with a native wildflower and grass mixture. We installed drip irrigation and covered the slope with rolled burlap and stone rip rap.


In a few years, there should be many soil holding native plants putting roots out and further stabalizing the network of anchors.

rip rap

For whatever type of land restoration we are doing there will be plants involved. The plant roots are the binder that hold the soil together and so it is very important to choose the appropriate plants for the application and to focus on proper establishment of those plants so that they create healthy, extensive root systems and eventually thrive all on their own without supplemental irrigation. Drip Irrigation systems are ideal and most successful for this purpose but there are other methods that we can employ if drip irrigation is not feasable. Alternative Irrigation Systems for Arid Land Restoration.pdf explains several different ways to establish native desert plants including watering by hand.

The Soil

Soil is a product of climate, landscape, organisms, parent materials, and time. Generally we could say that our soil is going to be alkaline, heavy in clay and low in organic matter. What you might want to know next is the percentage and composition of soil components, the ratios of sand, silt and clay. There is a pretty easy and fun way to do a soil texture test and that is the mason jar test. Once you do the mason jar test you will have a better idea on what you have to start with.

Pro Tip

Don’t let silt fool you into thinking it is clay. Silt and clay are both extremely fine textured soils and it is very hard to determine with the naked eye which one is which. The mason jar test will make it apparent what your porportions are as the silt will settle out within 30 minutes but the clay will take much longer to settle.

Now you know the composition of your soil what do you do with it? Is it around 30% clay and a good ratio for making adobe brick, cob or earthen plaster? If it is not the perfect mix could you add more sand or straw or clay? Get your hands dirty and make a few test bricks, is this fun for you? If it is fun then you should keep exploring using the soil as a building material, if it is NOT fun then definitely move on because building with Earth is labor intensive and it is a big commitment.

Building soil for growing

All soils need more organic matter to support new life. Organic matter clusters the fine clay into crumbs, leaving more space for air and water. It acts as an underground sponge and holds onto water longer than the surrounding soil and increases the biological activity of the soil. Organic matter is the #1 additive to build your soil in just about any climate except for the rain forest. Go forth and find and collect organic matter!: leaves, hay, donkey poop, grass clippings, cardboard, potting soil, sawdust, tree bark shavings, shredded paper, coffee grounds, your neighbor’s coffee grounds.

Pro Tip

Do you know this ONE EASY TRICK to get FREE organic matter? It’s just lying there in the arroyos, creeks, and rivers.
I was able to collect 60 gallons of pure organic matter from this creek at a single location after a flood. When it floods again, it replenishes itself. Do not go onto land that is not yours without permission, that would be stealing, but look around your land and see if you can find some brown gold!

collecting organic matter from flood

Now that you have collected some free organic matter what do you do with it? There are some questions to ask yourself first:

  1. Is there any chance that this organic matter could be from a poisonous source?
    Is it from treated or painted wood? Does it contain datura, oleander, sago palm or any other plant know to be poisonous to animals?
    If yes, put it in the elimination pile and bury it. The elimination pile lives where there will never be any food grown and no domestic animals can get to it.
    If no, proceed to next question
  2. Are there any thorns, glochids or cactus spines in this organic matter?
    If yes, it goes into a pile that is designated for pokey things, this pile will sit for a long time before we finally do anything with it.
    If no, proceed to next question
  3. Does this organic matter contain poop from any domestic animal?
    If yes, it goes into the HOT COMPOST pile or gets directly buried in a planting hole for a non-edible perennial tree or shrub
    If no, proceed to next question
  4. Is there any chance that this organic matter contains invasive weed seeds?
    If yes, it goes into the HOT COMPOST pile or gets directly buried in a planting hole for any perennial tree or shrub.
    If no, it goes to the cold passive compost pile for later building the hot compost.

As you can imagine I have several different holding areas for organic matter because you never know when you are going to strike it rich with brown gold. These different holding areas I have placed specifically for future plans of certain garden areas or trees. So even though I am not ready to plant yet, I’m still working on building the soil where I want my future gardens to live.

For additional information on building soil, check out these two articles by John Cappadonna: Compost and Composting Hot or Not

True story: I happend to be in Alpine in the fall with a completely empty 15 passenger van, and happened to drive by the courthouse where they had stacked bags upon bags upon bags of leaves raked up from the lawn. Well it did not take long to find the person who told me YOU CAN TAKE ALL YOU WANT! So I stuffed the entire van full of bagged leaves, smooshing the bags into the doors as I shut them, there was only room left for me to drive. What a score that was! (and free trash bags to boot)

If you work at building your soil you can have some really beautiful gardens here. From native landscaping to veggie gardens, the soil is the most important part. It is a slow process and it takes some years before you can say you have truly changed the desert into a garden. However if you skip this step and plant things without building the soil it is like painting over duct tape, it may look okay for a while but it will never work long term. Take the opportunity to visit the Terlingua Community Garden in the Ghostown if you have not visited in a while. What was once a junkyard in 2006 has been turned into a food producing oasis simply by building the soil.

Things to avoid adding to your garden soil

  • Egg shells, increases the calcium levels of the soil
  • Lime, used to raise the pH of acidic soils, we don’t need it here
  • Wood Ash, same use as lime, we don’t need it
  • Table salt, sodium laurel sulfate based cleaners, increases sodium levels

Soil compaction

is also something we want to avoid, not only does it hurt your back, it hurts the plants too. Without getting into too much science here, compacted soil impedes gas flow from the soil leading to potentially toxic levels of CO2 gas locked underground. Plant roots need oxygen but they can’t get it because of the compacted soil and eventually the plant may die if the situation is not corrected.

Here is an example of this in real life. We put roads in on our property in 2012 and I made an effort to put the road in a place where we would not have to remove several mature ocotillos. I began to notice about 2 years ago that one right beside the road was not looking so great. It was not one of the oldest ones and should not be dying of old age just yet and I began to suspect that the soil compaction of the road, over the root zone of the ocotillo was making it die. Of course I could not convince my other half that we should move it. About a year later we had a severe storm with high winds and sure enough, it toppled to it’s complete death. Not only that, wow! we lost 3 ocotillos at the same time, all toppled by the wind and consequently, they were all right beside the road. Well now that I have made this mistake, you don’t have too.


Think about the impacts of development, erosion, compaction and soil fertility as you design your space. If there is a place where you want to plant a tree later, mark it off now so that no one drives there and compacts the soil. Put your collected organic matter in that spot and start building soil instead of decreasing soil fertiliy. It takes a while to build a homestead from raw desert land but the little bits of progress add up and eventually you will get there.