With the ongoing droughts, water shortages and rising cost of water supplies, many homeowners are considering rainwater harvesting and storage to tide them over the dry spells, or in some cases, even going off-grid with water completely, in order to lead a self-sufficient lifestyle.
Regardless of whether you are hoping to cut down on your water bill, be completely self-sufficient, or simply conserve water due to environmental issues, going off-grid with water while living in an urban area is completely feasible — even in areas that do not receive lots of rain.
But before you can cut ties with your water utility, you will have to find a water source to tap into. If you have a dam or a stream on your property, you can use this as your water supply, or you can drill a well to tap into groundwater. For properties that don't have access to water onsite, rainwater harvesting is the only option, and for most urban residential areas this is the most feasible water source. An additional benefit of using harvested rainwater for drinking purposes compared to other sources of water is that rainwater is pure and contains no contaminants or pathogens that can be harmful to our health. By comparison, groundwater and surface water often contains a wide range of pollutants that need to be removed before the water can be used for drinking purposes.
Rainwater Collection and Storage Options
Any structure with a roof surface can be used to collect, harvest and channel rainwater to a storage tank so that it can be used as needed. The stored rainwater can be used for a wide range of household uses, including domestic use, irrigating plants, washing your vehicle, topping up the pool, or providing drinking water for livestock, pets and even human residents.
A rainwater harvesting system consists of the following components:
- Catchment surface — typically a roof, but decks and other surfaces can also be used as a catchment
- Diversion system — this channels the collected rainwater to your storage system
- Storage system — rainwater barrel/s or cistern/s that store the collected water for you to use when you need it in the future
- Distribution system — water pipe network that distributes the stored water to your home, garden, swimming pool, etc
- Treatment system — the system you use to filter or treat the water to render it suitable for the purpose you intent to use it for
When choosing rainwater barrels or cisterns for your storage system you must ensure that they are safe. Rainwater tanks must seal securely to prevent pets or children from falling into them. They should also be constructed from food-grade material so that harmful chemicals do not leach into the water stored within them, particularly if this water is going to be used for drinking purposes.
Above-ground rainwater tanks offer a popular water storage solution for urban residential areas as they are available in a variety of different sizes, shapes and colors to enable the homeowner to find an aesthetically pleasing solution that will fit into any space on their property.
Cisterns are another option for storing a large volume of water either above or below the ground. Cisterns designed for use below the ground are usually quite bulky, but they are able to store large volumes of water without taking up space in your garden that can be used for other purposes. Cisterns designed for use above the ground tend to be smaller, and consequently lighter. This makes them more portable as they are easy to move around.
If you plan on using the harvested rainwater for drinking, it is advisable to treat it beforehand to ensure any potential contaminants are removed. While the risk of contamination is much less than that of other water sources, bacteria, as well as sediment, debris and other particulate matter together any chemicals on the roof surface, can flow into your storage barrels and contaminate your water. To prevent this, it is essential that you have a pre-storage treatment mechanism installed to remove some of these pollutants before the water flows into the storage tank, followed by an after-storage filtration system such as a Berkey water filter that will remove any contaminants that may be present and render your water safe to drink.