Frequently asked questions


What is Canal de Isabel II?

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Canal de Isabel II is the company responsible for the management of all stages of the integral water cycle in the Community of Madrid. It is more than 165 years old and currently supplies over 6.3 million people living in Madrid. Canal is a trailblazing company and leader in its sector, as well as an international reference point thanks to the quality of its service.


Canal’s reservoirs can store up to 944 cubic hectometres of water

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Surface water is stored in a network of 13 reservoirs located on seven river basins in the Sierra de Guadarrama. The maximum storage capacity is 944 cubic hectometres, almost twice the amount of water consumed by the entire Community of Madrid in one year. This amount of water could fill 940 football stadiums the size of the Santiago Bernabéu. 


Canal’s distribution network is over 17,000 kilometres long

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If we placed all the pipes that transport water to users in a straight line, we could go from Madrid to Sydney, in Australia.


Canal’s 14 treatment plants are capable of purifying 52.3 cubic metres of water each second

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The treatment capacity of Canal’s plants is 4.55 cubic hectometres per day. The largest of the 14 treatment plants is the one in Colmenar, with the capacity to treat up to 16,000 litres of water per second. The oldest drinking water treatment plant in the Community of Madrid is the one in Torrelaguna, which began functioning in 1967.


The water purification procedure is carried out by 6 connected processes

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Pre-oxidation; coagulation and flocculation; settling; filtering; neutralisation; and final disinfection are the phases the water goes through in the purifying plants. You can find out more about each process in the integrated water cycle chapter.


Canal has 157 wastewater treatment stations

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The 157 wastewater treatment stations form part of a series of installations responsible for the wastewater sanitation systems. This complex system is made up of sanitation networks and municipal sewage systems (sewers and outfalls) wastewater pumping stations, storm tanks and the actual waste water treatment stations. In total, the purifying network covers over 14,000 kilometres and is capable of treating up to 3.20 cubic hectometres per day. This sanitation process fulfils an essential mission for the environment, since the water is returned in optimal condition to rivers and it can be reused for various uses unrelated to human consumption.


What is meant by the term 'reuse'?

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Reuse is a process in which treated waste water receives an additional treatment to allow it to be used for industrial purposes, for cleaning the streets and for the irrigation of green zones. Thanks to this reuse, water is given a new life, and it is not necessary to use drinking water for these activities: this represents a significant commitment to the environment and sustainability.


Canal has 65 storm tanks that store rainwater runoff

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Storm tanks are enormous underground deposits that store the first rainwater, which is the most contaminating water, since it brings with it all the dirt accumulated in public spaces. They also prevent the treatment plants from exceeding their maximum flow and having to dispose of excess amounts, without being treated, into receiving waterways. Canal de Isabel II has 65 storm tanks that store rainwater before being treated. In total, they can store 1.46 cubic hectometres. The largest of these is located underneath the Villa de Madrid golf club practice area in Madrid. This deposit, the largest storm tank in the world, can store up to 400,000 cubic metres of water, eight times more than the El Retiro lake.


How much water do we consume in Madrid each day?

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On average, each person in Madrid consumes 122,33 litres of water per day.


Why is the water in Madrid so good?

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The sources of supply, in the hills to the north of Madrid, are in granite areas: this means that the salinity of the water is much lower and gives the water its pleasant taste. In addition, we watch over the quality of the water from the source. It is analysed in the reservoirs at different depths and the best available quality at any moment is selected for consumption.

This quality at source, combined with advanced purification processes and continuous quality controls, serves to guarantee that the water coming out of the taps in Madrid is top quality.


Canal carries out more than six million analyses of drinking water per year

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As a result of the application of a strict drinking water monitoring programme, Canal carries out more than six million analyses of drinking water each year, to guarantee the quality of the water when it reaches customers. The programme is designed to monitor the quality of water intended for human consumption, before and after the treatment process and during distribution to users. It enables a permanent alert system to be maintained, via 40 automatic monitoring stations (EVA). Apart from controls carried out on drinking water, Canal repeats this monitoring process with reclaimed water. It also carries out over 1.5 million analyses of recycled water each year.


The remote-control system has around 30,000 sensors

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The remote-control system enables the water situation of the collection, distribution and sanitation infrastructures to be known in real time; the quality of the water and other important parameters for managing the comprehensive water cycle. With around 30,000 sensors deployed in 2,369 locations and supported by a state-of-the-art telecommunications network, the remote-control system is an essential tool for monitoring the infrastructures of all the phases of the integrated water cycle.


The residents of Madrid consume the lowest amount of bottled water

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The Community of Madrid is the region in Spain in which the lowest amount of bottled water is consumed. According to figures from the Ministries of Agriculture, Fisheries and Food and the Environment (MAGRAMA), in 2016, each resident of Madrid consumed an average of 14.23 litres of bottled water, a much lower figure than in other Autonomous Communities. The Balearic Islands is the highest, with 114.41 litres per inhabitant. Immediately above Madrid is the Basque Country and Navarre, with 18.73 and 21.71 litres per inhabitant respectively. This firm commitment to the consumption of tap water in Madrid is partly due to the extraordinary quality of the water, since it is painstakingly treated and controlled from its origin until its distribution to users.


Why should you never flush wet wipes down the toilet?

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Wet wipes, like all solid waste that is flushed down the toilet, cause major environmental problems. Although wet wipes are biodegradable, they do not break down in the few hours it takes to reach the waste water treatment plants. This is the reason they cause blockages in private homes, in the main sewage system, and in the treatment plants. While toilet paper breaks up within a few minutes of being flushed down the toilet, this is not the case with wet wipes, or with most feminine hygiene products, cotton buds, condoms, etc. which are so often thrown into the toilet. So, remember, wet pipes always go in the waste bin.

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