Off The Grid Living Part Three: Waste

By Matt Valzania

In two other articles found on LandCentral’s Land University, I discussed two of the most vital systems needed in off the grid living, water and power. The last item that needs to be addressed no matter where you live is how you plan on dealing with your waste. This less than glamorous subject can sometimes be forgotten but it doesn’t take more than a day or so without the proper accommodations before you realize you’re either roughing it or living the civilized life.


It’s Not Just Black and White When It Comes to Waste

There are a few options when it comes to dealing with waste. Before we address those I should probably mention that waste can be broken up into two categories, gray water and black water. Gray water is the water/waste that comes from washing dishes, taking showers, and the like. As mentioned in my Living Off the Grid – Water article, gray water can be reused for things like watering flower beds or refilling toilets however once this water has been “utilized” in a toilet and gets flushed, it is considered black water. Black water then needs to be properly disposed of to eliminate the possibility of bacterial hazards in your home. This waste can be useful though, because if treated properly, it can make for great compost fertilizer for your gardens. In this article I will solely present ways to deal with black water as gray water, if not used for any other purpose, can be plumbed into the black water system.


What is a “Perc” Test?

Perc Test From The Scott Arboretum

A discussion on septic systems is not complete without touching on the subject of percolation, or “perc”. When people talk about perc, they are referring to how well the soil drains water. Courser granule-like soils such as sand will perc the best, whereas soil with high clay content will drain poorly. An ideal type of soil is like that found in Imperial County, California which is comprised mostly of dune sand, sandy loam and Imperial loam. When choosing the home site on your property, the perc test is one of the most important tests you should do prior to getting too far into the build as it can drastically alter your plans on where to build. With all that being said, just because your property may not drain well does not mean that you cannot build there. It only means that your method of dealing with the waste will have to be modified accordingly.

The University of Minnesota has a great guide on how to properly perform a percolation test. Of note is that if your perc rate is slower than 60 MPI, or minutes per inch, then a standard drain-field septic system will not be suitable and other methods of waste disposal will have to be considered.


Send it to the Field

Image Credit: Catawba Riverkeeper

The most common method of dealing with black water is via the conventional septic system that utilizes a tank and leach field. This is by far the most widely used system for rural or remote properties with approximately 25% of all homes in the U.S. utilizing this form of septic system. The waste from your home flows out of the home via a large pipe and enters a large below ground tank. This tank can be constructed of a number of materials but the most common are concrete or plastic. The size of the tank is largely determined by the size of the home it’s being connected to. For example a four-bedroom home might require a 1200 gallon tank although local code will also affect the sizing requirement. Aside from construction material, tanks come with either one large compartment inside or they may be divided into two compartments. It is said that the dual chamber tanks are more effective at sorting out the solids from the liquids and therefore less likely to allow solids into the drain field which can save you huge headaches down the road from having to service your leach field due to clogged pipes. Some zoning codes even mandate a two-compartment tank so be sure to check your local zoning prior to making your decision on the type of tank to use.

Once waste goes through the tank, the leftover liquids flow out the overflow outlet into a distribution box. This box is purely a manifold in which multiple runs of pipe can be connected. From here these runs of perforated pipe are laid out in a specific pattern as determined in large part by the perc rate of the soil in your area. A septic engineer will prescribe the size of the leach field needing to be used dictating the length and number of the perforated pipes. For optimal performance, these pipes lay on a bed of crushed stone and then are surrounded by a buffer layer of packing-peanut like tubes or other covering material which help to keep soil from plugging the pipe perforations. Once all this is installed to spec, the trenches get backfilled level with the surrounding soil.

As mentioned earlier, if your soil fails to percolate to a required minimum, you can use a modified version of leach field known as a “raised bed”. This field still uses a tank and perforated pipe however instead of the pipe laying in dug out trenches directly in the soil, a layer of sand fill is brought in and spread out on top of the existing soil first followed by your piping and more sand. Finally a layer of top soil is spread on top of this to provide grass or other plantings a hospitable home. The biggest drawback to this system is the extra expense of hauling in sand and dirt. There is also the possibility a pump will be needed to get the waste out to the field however this is dependent on the grade of your property and the height of your home and septic tank. West Virginia University published a great article explaining raised beds in further detail along with providing additional resources for further research.


What Else Can I Do?

If utilizing a standard septic system is not in the cards for your particular situation or needs, there are some other options, namely composting toilets or outhouses. Both of these options will have a bit more impact on your daily life as they will require some degree of continual maintenance and may introduce unwelcome odors if not managed properly.

Image Credit: Green Resistance

Composting toilets work on the principal that human waste is compostable and can be quickly achieved via aerobic decomposition. A few facts about composting toilets goes as follows:

  • Composting toilets use nature’s decomposition process to reduce waste by 90% and convert it into nutrient rich compost.
  • They do not require water hook ups either which is great for our already stressed water supply. In short, composting toilets are a way to allow waste to decompose safely and without odors.
  • Composting toilets use oxygen loving bacteria that is naturally present in human waste to do all the work.
  • Bugs, worms, and other critters have absolutely NO role in the composting process.
  • The material you remove post decomposition is no longer waste, its nutrient rich compost.

There are both do it yourself and commercial composting toilets available, both of which achieve the same overall result. The basic concept is that waste enters a chamber where it is left to aerobically decompose. Typically an additive like sawdust or peat moss is also introduced to increase the decomposition rate. This chamber can have some form of mechanical agitator to aid in the decomposition rate. Liquids that enter the chamber are diverted to a drain where they are separated and left to evaporate or leach into the ground. Commercial versions of composting toilets can include a heater and vent fan that help to maintain a proper and consistent heat level which helps to speed up the decomposition process and help regulate odors. The biggest benefit to composting toilets is that after the waste has been broken down, you are left with a nutrient rich fertilizer that is perfect for plant beds.

A great technical reference on how composting toilets work is available in the Composting Toilet System Book, of which an excerpt can be found here.

DIY Outhouse

The last and most basic option is a good ol’ outhouse which is for all intents and purposes, a sheltered toilet seat placed atop a large pit. Waste is left in the pit to decompose naturally over time. Sawdust or peat moss can be introduced to aid in decomposition however this is not necessary. The difference between an outhouse and a composting toilet is that the waste is left there indefinitely instead of getting removed as a usable by-product. As the name implies, outhouses are usually a separate structure built away from the house to keep any uninvited odors from entering your home.

As mentioned, these systems usually need some type of user assistance for them to function properly, not as much with outhouses. With that being said, composting toilets and outhouses are great options for an off the grid home that has limited supplies of electricity or water as neither are needed in these method’s most basic forms. With the use of water efficient toilets, using a standard septic system is still a viable option even when using a limited supply of water.

If this is the first article you’ve read of our Off the Grid series, be sure to check out the others within the Land University along with a ton of other useful information pertaining to buying land.

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