Why Rainwater Harvesting Is So Important

Globally, water is without a doubt our most precious resource, and with the proliferation of jabber we hear on a daily basis about climate change, many are finally waking and have realised just how limited and precious our water supply is to our survival.

Consider this alarming fact, the world’s primary water sources, our groundwater supplies are drying up; a recent study revealed 21 of the 37 largest aquifers are depleting faster than the replenishment rate with an additional 13 aquifers which are declining at a rate which NASA calls “troubling”.

The report hits close to home, quoting the Canning Basin in Western Australia’s northwest as one of those resources at serious risk of drying up. In fact; a recent report from NASA University found that 11 per cent of disappearing groundwater is used to grow internationally traded food, you can see the article here.

Furthermore a recent report from DW reported that the worlds vital lakes are disappearing with water scarcity a growing problem worldwide, Africa, in particular, has been hardest hit. Despite popular belief that climate change is purely to blame, in many cases, the direct depleting of our natural water sources is to blame, diverting sources of replenishment directly to areas for agricultural and mining purposes. The demise of Lake Poopó is a good example where empty fishing boats sit on a cracked lake floor, not only has a water resource disappeared but also a food source.

The History of Rainwater Harvesting

Rainwater collection has been around for thousands of years, the process of collecting surface runoff and channelling that water directly into storage tanks, homes and a larger scale; the process of directing water through aqueducts channels water directly to arid lands or cities.

The way in which people live has changed, less subsistent living and greater reliance on city dwelling, methods of collection, storing and channelling water changed as populations grew, moving away from living on the land.

As a result in modern times, rainwater collection has become less widely used, although it remains commonplace in rural areas. Rainwater runoff from rustic rooftops is often channelled into water storage tanks and used in most cases as a secondary water source for reducing home water usage or as drinking water for farm livestock such as sheep, horses and cattle with cows alone drinking up to 150 litres of water per day.

Rain Harvesting in Australia

According to the ABS, approximately 26% of households in Australia (roughly 1 in 4 homes) engage in rainwater harvesting which caters for 9% of all residential water requirements.

The conservation of our water supplies by reducing demand on our dams and storage reservoirs through rainwater harvesting has a direct benefit to residential home-owners in the reduction of their quarterly water bills.

rainwater harvesting

How We Use Our Water

Water consumption varies significantly throughout Australia; however, the average household uses 900 litres of water daily. If this seems utterly unbelievable, consider the following facts;

Washing Machines
Particularly greedy consumers of water, even energy efficient machines consume around 58 L per cycle, some of the older washing machines require up to 170 L per cycle, top-loaders typically use the least amount of water and tend to wash better.
Brushing Teeth
If you leave the water running while you brush you will typically use around 22 L each time your brush.
Showering
Just a five-minute shower consumes around 67 - 112 L, variations in water pressure and the type of shower head directly affects water usage.
Flushing Toilet
The average family of four uses 3,960 L of water per week flushing their toilet, that’s 141 L of water daily per person.
Washing Hands
Every time you wash your hands you use approximately 18 L of water.
Washing Dishes
If you leave the water running while you wash you can use up to 150 L compared with dishwashers which use approximately 18 - 27L per cycle.
Washing Car
Washing your average family car can use more than 300 L.
Watering Lawn
Watering your garden with a typical sprinkler system for 1 hour will use 4,590 L of water.
Personal Intake
It is recommended the average person drinks around 2 L of water daily; this amount varies on temperature, how much you sweat and exercise.

How Much Can Water Be Harvested from Your Roof?

The amount of water harvested from your roof depends on its area, the average rainfall and the location of your home. Homes located near the coast of the NSW Central Coast get approximately 1200-1600mm of annual rainfall. If you live in a medium size home with a roof area of approximately 150m2 the amount of water able to be harvested from the catchment area would be 180,000 litres, given the average household consumption of 900 L per day, this represents up to 180 days or 6 months of water savings, a potential to cut your water usage in half.

How Much Can I Expect to Save Rainwater Harvesting?

If you were to factor in watering your lawn once per week for one hour, then this would use all of the water that you have harvested and a little more. Of course not all homeowners water their lawns weekly; however, consider the potential annual cost savings on 180,000 litres of water amounts to approximately $414.00.

Rainwater harvesting is more about saving money, according to UNESCO, due to population growth, urbanization, industrialisation, and increased production and consumption have generated an ever-increasing demand for freshwater resources, by 2030 (less than 12 years), these demands are projected to result in the world facing a 40% global water deficit under the business-as-usual climate scenario (2030 WRG, 2009). The calming element of these alarming facts is it is possible to meet the world’s growing needs if we dramatically change the way we manage and share our water rather than our resources lack of availability.

How Can I Best Use Harvested Rainwater?

There are various ways to use harvested rainwater, NSW Health reports that in residential areas the public water supply is the most reliable source of good quality drinking water for the community. The report further mentions that NSW Health supports the use of rainwater tanks for non-drinking purposes such as watering the garden, cleaning the car, filling swimming pools, spas and ornamental ponds and firefighting.

Livestock Rainwater Harvesting

Demands for the commodity meat is increasing annually, and the reality is that farming livestock and catering for their needs is an ever-present concern. Cows consume an incredible amount of water consuming up to 150 litres per day, the cost of which equates to approximately $65 annually. Due to the thirsty nature of these beasts, rainwater harvesting is an obvious solution; research shows that significant savings are possible by the more practical use of rainwater harvesting.

In rural areas catching water from building downpipes not only reduces residential use but by stopping runoff before in it lands on vulnerable farming areas has added benefits. But rainwater harvesting is not limited to catchment from building roofs; stand-alone constructions purpose-built for rainwater harvesting and ground run-off are other opportunities for rainwater harvesting.

Is Drinking Rainwater Safe?

Drinking rainwater which has not come into contact with the ground is very safe, once the rain makes contact with any surface we have to be aware of the dangers of contaminants which may have affected the water supply as highlighted within the NSW Health report.

To safeguard the integrity of the water; it is crucial to prevent leaves and roof contaminants from entering the tank and perform regular checks, taking preventative measures to ensure that mosquitoes are not breeding in the tank.

If you wish to drink tank water there are methods which enable you to purify the water, so it’s fit for human consumption, this process is known as water purification.

Water Purification & Distilling

There are various ways in which to remove contaminants from water however the two primary methods are water filtration and distillation. Distilled water, which is the purest form of water contains no contaminants, all bacteria, viruses, heavy metals and chemicals are removed directly as a result of the distillation process, making it suitable not only for personal consumption but also pharmacological, chemical and industrial purposes.

As far back as 400 BC the Phoenicians who were great sailors had mastered a technique which allowed them to spend extended time at sea without taking onboard water supplies.

How did they do this? Well, the Phoenicians were able to filter water through purpose-built clay pots. Creating these pots involved a process of combining either flour or activated carbon into the clay along with colloidal silver. After moulding these contents together in the clay mix, it was shaped into a pot and fired. As flour or carbon particles are just 1 micron in size, the process of blending it into the clay created millions of small imperfections in the pot during the firing process, making the pot porous.

The Phoenicians dragged these porous pots behind their sailing vessels, as seawater passed through the porous pot, salt being larger than 1 micron was filtered out. Furthermore, colloidal silver which had been added into the clay purified the water as it passed through the pot killing any bacteria present in the water.

Today, water purification systems provide a more natural way to purify water quickly and easily. Purifying water for human consumption can be done using one of three methods; water purification tablets, water purification systems or distillation.

Purification Tablets

Purification tablets are a great way to purify water from sources where the quality is questionable, for as tap water in some overseas locations, hiking or emergency and survival situations where there is no immediate availability of clean water. When purchasing purification tablets, it is important to do your research as some brands have questionable additives while others.

Water Purification Systems

Second to water distillers, water purification systems filter out the majority water contaminants; however it does not remove viruses as some chemicals and pollutants do remain, by comparison, however, compared to tap water, purified water is substantially better for your health. Some health experts argue that purified water is better than distilled water as distilled water has no minerals, however this argument easily flawed, as minerals can be obtained by the food we consume, a focus on a healthy diet is all that is needed.

Water Distillers

Water distillers are relatively affordable to purchase with household appliances ranging in price from around $200 - $400 for a 4L distiller. Distillation is a slow process; water needs to reach boiling point, at which the liquid starts vaporising. The moment water is converted to vapour it is pure leaving behind contaminants such as chemicals, minerals, heavy metals and viruses. The distiller’s task aside from heating the water is to capture the vapour, cool and channel the pure water runoff into a holding tank.

Distilled water is the healthiest water you can drink, and research has shown that it aids in cleansing your body of contaminant residue left behind from drinking tap water, contaminants which have been proven to cause numerous diseases within the body.

Prepping, Off-The-Grid Living

Rainwater harvesting is an effective strategy against adverse conditions whether those conditions are brought about through natural disaster or man-made, water shortages are a concern for all of mankind as it is essential to all life.

Rainwater harvesting is favoured by many who desire to live independently “off-the-grid” and those who take comfort in preparing for worst-case scenarios, often called preppers.

For those who are heavily reliant on water, having a backup plan is not an option, disasters do occur, having a failsafe plan ensures the continued running of your business, your agricultural or livestock concerns and your families or personal welfare is a wise choice.

Recap

We hope you have enjoyed our article if you feel that we have missed any relevant or essential information we would love to hear it.

In brief, this is what we discussed;

      Rainwater scarcity
      The history of rainwater harvesting
      Rainwater harvesting in Australia
      How rainwater can be harvested, collected, stored and filter
      Distillation and purification of rain.
      Living off-the-grid.

Resources

Four-page resource about rainwater tanks, harvesting water, consumption and tank maintenance.
Resource on rain harvesting techniques.
Information on how to find an irrigation specialist and timely information on rainwater harvesting.
Information on “off the grid” living and rainwater harvesting. A credible resource which discusses issues revolving around health and fitness.

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Graham Ross