There are a few options to be considered when contemplating water sources for off grid living.
The first method that comes to mind is Rain Water Harvesting. Rain water is probably viewed as the easiest and most affordable water source, provided that the harvesting could be done in a high rainfall area. Rain water is mostly harvested from rooftops and conveyed with gutters to storage reservoirs. Adequate storage is key to being dependent of this source. Rain water can be stored in a series of rain water barrels, flow bins, above ground rain water tanks or a series of those and even underground rain water tanks.
Checklist for consideration before it is decided to become dependent of rain water as a primary water source:
– Area rainfall history
Obviously, “rain rich” areas are best for harvesting rain water. It will be of no use to explore further on the subject if rainfall is historically low in an area. Do proper research on the historical rainfall figures of an area. Try to find information on historical drought periods in the area and the duration thereof. Visit the area and speak to the older people in the area. Lots of wisdom on weather patterns are often heard from the people who grew up in a specific area.
– Duration of the rainy season
If for instance the rainy season is for a period of three months of a year only in an area, you will need to have adequate catchment and storage to bridge your water supply for a 9-month period. This will rather stretch the resources that you will need to keep water in storage. In such an area, you will probably need a series of rain water tanks or even underground rain water segmented storage units, rather than a smallish rain water barrel.
Obviously, an area which has a longer rainy season will suit the purpose better.
– Rainfall frequency
Basically rainfall frequency has been touched on in both the previous items, namely rainfall history and duration of the rainy season. Higher frequent falls will fill and sustain rain water tanks more effectively than for instance when high volumes of rain are experienced, but with shorter frequencies. In other words, the same quantity of water, but spread over a longer period of time will have a more desired result in sustaining rain water storage supply than short high volume rainfalls.
– Rain water catchment surface
Roof tops are mainly used as catchment surface for harvesting rain water. It is a simple math, the larger the roof area, the more water can be harvested. It needs to be kept in mind though that roof angle alignment in relation to prevailing winds may influence the water volume harvested.
Gutters must be effective in channeling the water volume from the roof seams into the water storage units. The rain water gutters must have a large enough design capacity to lose little or no water during heavy downpours.
– Water Storage
When you decide on rainwater storage capacity, one thing is a fact and that is: “size matters “
Start by determining your daily water consumption. I promise you, it is much more than you initially thought you were using. Factor the daily use into the period that water storage is needed for and BOOM! …You need the size of Everest for storage. …At least this is how I felt when I initially did the math 😉
Though rain water harvesting may be viewed as an economical way of off grid water supply, the challenge of this option remains sustainability during the dry season.
The dry season always seem too long and storage capacity is always inadequate.
– Rainwater harvesting can be very cost effective.
– It is however difficult to be fully self-sustaining with rain water as primary or only water source.
– It is ideal to combine rainwater as a secondary and cost effective supplement to another primary water source.
Other off grid water sources that may be considered:
– Sand water well point