Living Off The Grid

This is the first of three articles about water, its sources, treatment, use, and potential reuse when living off the grid.
By L. Fred Roensch, PhD

Part 1- Water-Yes we need it off grid but you should test the water before you buy land! Here’s why!

It is generally accepted there are four basic human survivals needs when living off-grid. They are shelter, heat/energy, food and water. The following three articles will focus on water, its collection, treatment, use and reuse. In this article the most common water sources (well, stream, pond, roof, etc.) and some of their potential problems, concerns and requirements for use and reuse are discussed.

Well Water or  “Ground Water”
Since the water is collected from below the surface, well water is classed as “ground water”. Well water usually has a higher dissolved soluble ion content but little or no insoluble suspended solids.  Because the water has probably passed through rock formations the water is usually “hard” water, i.e. high calcium and magnesium.  Therefore untreated well water often causes significant deposits, particularly in the hot water part of the system. Usually these deposits appear as rings or “scum” in plumbing fixtures. These deposits, as time passes, become very hard to remove. At the very least they require periodic cleaning.  Eventually, these deposits will result in premature failure of the plumbing valves and fittings. Also, usually, more detergent or soap is required for cleaning and laundry when using well water.

The hardness can be removed by passing the water through a sodium “zeolite” (strong cation ion exchange) softener that has been regenerated with salt.  The calcium and magnesium will be removed and replaced with sodium ions. The water is then called softened water. Usually, the increase in sodium is not a concern. However, if a low sodium diet is required, depending on the amount of sodium added, softened water could be a concern. Because the calcium is removed softened water is corrosive to metals, especially when heated. Therefore, this fact should be considered when selecting the materials of construction for the water distribution system.

An alternative to softening all the water is to soften only the water which will be heated. Unsoftened cold water is unlikely to cause deposit problems.

Although not a health concern, well water often has iron and/or manganese contamination. Some or all of the iron and manganese is usually dissolved in the water and will pass through a particulate filter.  Iron and /or manganese can cause unpleasant taste and create red, brown and/or black deposits especially in the fixtures of the system. such as sinks, bathtubs and toilets.

If iron levels are high the iron can be reduced to an acceptable level by oxidation or aeration followed by filtration.

Manganese is much more difficult to completely remove. Unfortunately, even a trace of manganese can cause black deposits to accumulate in the system. The small amount of soluble manganese will be oxidized by air or by free chlorine residual, if present. This is particularly true when the water is heated.

In addition, in some cases, the water contains the gas hydrogen sulfide.

Hydrogen sulfide causes the water to be very corrosive to metals and has a rotten egg odor.  Dissolved hydrogen sulfide is difficult to remove completely. Only a portion of the sulfide will be removed by aeration and oxidation followed by filtration.  Oxidation will result in insoluble elemental sulfur particles that are very fine and require filtration to remove. If no filter is present then yellow elemental sulfur deposits will appear in the system. Some of the hydrogen sulfide will not be oxidized and create odor when the water is exposed to the atmosphere in toilets, showers, washbasins, etc.  Complete removal of sulfide requires a series of treatments including aeration, oxidation, and filtration or in extreme cases, treatment with a strong oxidant such as chlorine dioxide.

In the worst case, the well water contains high calcium, iron, manganese, and sulfide.

Usually, radioactivity, chlorinated organics, pesticides, antibiotics, pharmaceuticals and contamination from sewage (possible pathogens) are not a concern. That does not mean they are never a concern-but at least most of the time they are not a concern if the placement of the well is optimized to minimize contamination from bacteria or other organic contamination. Complete testing of a representative water sample is strongly recommended.

Some shallow well water is very “soft” (low calcium and magnesium) and does not contain a significant amount of iron, manganese, or sulfide. That might seem ideal.  However, this type of water quality can be very corrosive to steel and copper lines and all plumbing features. As we learned in elementary school, “water is the universal solvent”. This is especially true if the water is very pure or nearly pure.

If well water is planned to be the principle or sole source of water and no well is present then a test well is highly recommended before purchasing the land. If a well is present a complete inorganic and comprehensive bacteria test including coli forms should be preformed on a representative sample. Contact your local certified water test laboratory for sample bottles and instruction for sampling and submission of sample. Usually, the water sample analyzed for coli form bacteria must be stored on ice and submitted within 24 hrs or less.  In addition to the typical dissolved ions, be sure to include iron, manganese, sulfide, and conductivity, pH and bicarbonate in the analysis.  Depending on the results of the analysis, the appropriate pretreatment process and equipment to minimize or eliminate potential problems can be budgeted. In extreme cases the location of the proposed well may need to be changed.

Generally, if the well is properly placed, bacteria are not a major concern in well water.  Nevertheless if the well water will be used for drinking water the water should be tested for the presence of coli forms (. E. Coli is the indicator organism). If they are detected it means the water is likely contaminated with waste from humans or other animals.  Obviously, to maintain good health and reduce the potential for water borne disease, treatment to consistently eliminate bacteria and other organisms is recommended.

In some cases the well may have to be moved or the well avoided totally.

Usually, well water used for drinking and other potable water uses does not require filtration through granulated “activated” carbon (GAC) filter to remove organics. In many cases the well water does not need to be passed through a particulate filter. Of course there are exceptions where the water is contaminated with unacceptable organic molecules. If organics are present, it may be necessary to pass the water through a GAC. or through reverse osmosis (RO) to remove virtually all the dissolved solids and higher molecular weight organics.  However, since the water will have virtually no calcium, reverse osmosis treated water will be corrosive, especially when it is heated. The water may need to be treated to reduce its corrosiveness.  In addition, the corrosiveness needs to be considered when selecting materials of construction of the water distribution system.

To optimize its useful life, be aware all oxidants must be totally removed from the water before passing through a RO unit. This is because the membranes (in all small home systems) are very sensitive to oxidants. As a result the water is usually passed through a GAC to remove the oxidants. Unfortunately, the GAC, unless frequently changed, will act as source of bacteria that foul the membranes in the reverse osmosis device.

Surface waters- Streams, ponds, lakes, rivers, spring, and roof-collected water
Generally, surface water has lower dissolved solids and therefore the water is usually not high in calcium or magnesium. In addition, generally iron and manganese and sulfide are not a concern. However, there are exceptions. Some surface waters have all of these contaminates present. What is usually a typical concern with surface water are suspended solids. Suspended solids are insoluble particulates (in contrast to dissolved ions) that are not dissolved in the water.   Therefore, if the water from the roof or from a surface water source such as a stream or pond is used for domestic water, filtration is nearly always required to remove the suspended solids.

In addition, bacteria are usually much higher in surface waters compared to ground water. Treatment to consistently destroy all of the bacteria is required if the surface water will be used for potable drinking water use.

Water collected from the roof of a home is likely to be much lower in dissolved solids, even less than water from most rivers, streams, creek, pond or other surface water. As a result collected water from the roof, after filtration to remove suspended solids, is usually excellent quality water for watering plants, yards, gardens, and green houses.  A major reason why most off-grid homes prefer conventional roofs with gutters and downspouts rather than sod roofs is because collected roof water is low in dissolved ions, i.e. low salt content.

However, because the roof water has little hardness, water collected from the roof of a home will also be very corrosive to all metals, especially when heated. This fact needs to be considered in the materials of construction used in the distribution system if the water from the roof will be used for domestic hot water purposes inside the home.

The “take home” from this article: Water quality is critical for an off-grid home. Therefore before you purchase land for an off-grid home, have the water source or sources tested for inorganic, organics and bacteria.  Contact your local health authorities for specific sampling requirements, local certified laboratories and advice and interpretation of results of the tests. When in doubt, use a filter.