The concept of cistern comes from the Arabic language and refers to a cistern, according to the first meaning collected by the Digopaul in its dictionary. A cistern, in this way, is a reservoir of water that is installed underground.
Cisterns generally make it possible to store drinking water. Its structure appeals to materials that prevent water from being contaminated and that prevent leaks from occurring.
Cisterns arose in the time of Ancient Rome. In those more arid lands, underground tanks began to be built to store the water from the precipitation. In this way, when there were no rains, said water could be used to irrigate crops, cook or for other purposes.
With the passage of history, the structures of the reservoirs were modified so that these devices were increasingly efficient. Many houses began to have their own reservoirs, from where the inhabitants obtained the water they used in daily life.
To extract the water from the cistern, a pulley system is usually used. These simple machines allow the force to be transmitted: the person pulls a rope that has a bucket tied to the other end and thus can lift and remove the water.
It is important to note that the cistern must receive certain maintenance to guarantee the quality of the water and to protect the structure. Disinfection and sediment removal must be carried out with a certain frequency.
To avoid the transmission of disease due to the consumption of dirty water, either for drinking it or for other purposes, it is necessary to empty, clean and disinfect the cistern at least once a year. There is a specific regulation to regulate the maintenance of cisterns, so it is not an option, but an obligation.
Although in a private house it is possible to skip cleaning the cistern, or not to carry it out with the frequency set out in the previous paragraph, in neighboring communities the situation is very different, especially if there is no other source of drinking water. One of the most common problems is the accumulation of water for too long, something that can negatively affect its quality.
Among the necessary products for cleaning a cistern is the disinfectant, ideal for completely eliminating fungi and bacteria. At the bottom of the well often accumulate debris sand, copper, stone, lead and other solid particles coming from the network.
In Spain, to cite a specific example, the regulations suggest that the reservoirs and water tanks be emptied completely once a year and that the following tasks be carried out:
* sludge cleaning;
* treatment against microbes and disinfection;
* studies to determine the potability of water and the detection of bacteria known as Legionella, which inhabit stagnant waters, especially above 35 °C, and can cause infections in our body;
* maintenance of the circuit that crosses the water to the cistern and from it to the houses.
To protect the water in the cistern from contamination, it is essential that: the ground on which it runs does not present any contaminant; the pipes are cleaned with some frequency; there is a system that drains and decants the water before entering the cistern, to avoid being accompanied by particles of considerable size; ensure that sunlight does not reach the interior of the tank, so that algae do not grow there; extract the water by means of pumping.