EDITION: April - June '07


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Water in the home

Water is the source of life for all living beings. It is also the “universal solvent”, because the basic water molecule easily makes chemical bonds with other particles, while it just as easily breaks them, which means purifying water is also a relatively easy process.

Ibiza obtains the drinking water it needs thanks to fossil fuels, since sea water must be desalinized in order to satisfy the island’s demands (thereby using up a lot of energy = fuel). By reducing our water consumption, reusing water as much as possible, and recycling the rest, we are helping reduce the burning of fossil fuels (and therefore CO2 emissions).

Rainwater can be stored in cisterns placed under the house or in safareigs (outside open tanks) as the locals used to do, or in modern outside tanks that have a very reasonable cost and can also serve as ponds or swimming pools in the summer.

Reusing grey waters (from showers, washing machines and household sinks) onto the garden, or for flushing toilets, are a great way to avoid wasting valuable drinking water. Considering that the average person flushes between 20 and 25 tonnes of water a year down the toilet, which is on average between 30 and 45% of the water consumed in a house, this is a very important saving scheme, financially as well as energetically.


It is quite cheap and easy to install household systems to store grey waters in a cistern (if possible outside of the house to avoid the magnetic effects that any significant body of water has on us, as we saw in the previous article of this series), or in a small lake with fish and plants, for which it is important to use soaps and detergents that are natural or biodegradable. These waters can then be redirected to our toilets or to the ornamental plants in our garden.

Once used and reused (having become raw or black sewage), it would be desirable that we recycle our water, that is, that we clean it of foreign particles, purifying it. By doing so in such a way that the nutrients contained in this black sewage are not lost, but rather are recycled into food for our plants, we will be completing the natural process of water. Purification can be achieved through clarification or decantation, filtering, and the biological action of organisms such as bacteria, algae, fish and plants.

With any domestic system in Ibiza, if the septic tank follows present regulations (which implies the clarification and filtering processes are carried out within it), we can install after its outlet what is called a “green filter”, which is a way of cleaning water (especially of the bacteria that produce bad odour) using very little energy, and favouring biodiversity.

A “green filter” can be for example a lake system, made up of one or more lakes where the water is purified through the action of bacteria, plants and fish. This system can be truly decorative, giving our garden a ‘feng-shui’ feel. Another option is a system of vegetable peat covered lakes, where the lakes are filled with peat (vegetable earth), and which works thanks to the action of the rhizome bacteria of the plants we install in the peat, and due to the filtering effect of the peat itself. This method produces large amounts of wetland plants, such as bamboo or the beautiful calla lilies, giving our garden a lush fertile look. If our installation is balanced in the sense that the amount of black sewage we produce is proportional to the size of our purification system, it will give us no trouble and will require very little maintenance.


If we cannot install any of these systems, we can incorporate more conscious actions into our daily habits, such as recovering the water used in showers and sinks in buckets, and manually pouring it into the toilet instead of flushing, or onto our ornamental garden plants.

If our water consumption were proportional to its reuse and recycling, we would not have to worry about water restrictions or about reducing our consumption, as all our water would be constantly cycling. We would then be entering a truly sustainable cycle.