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The Drinking Water

By 25-07-2017April 28th, 2021No Comments

Information about drinking water



The water moves between the sea, the air and the soil in a circle called the water circle.
When the sun heats the rivers, the lakes and the oceans some quantity of water is evaporated . Then it getw colder as it goes up to the upper atmospheric layers (we call this condensation) and forms water drops, which join together and form the clouds.
As the clouds get colder, the drops of water become big and heavy and fall as rain, hail or snow. This is what we call precipitation.
The rain falls in the ground and the rivers and is driven to the lakes and to the seas.
And the circle of water restarts. Actually the water we use and drink today is the same used by the dinosaurs!


The drinking water can be of surface or underground origin. The underground water emanates from the water-bearigns stratum that are underground geological formations that have the ability to withhold rain water (atmospheric precipitations).
The city of Chania is supplied by the resources of Agia (the water is drawn before it reaches the lake) and additionally from the drillings of Miloniana (water of same quality).
The resources of Agia are a important aquatic resource with a total annual volume of 8 million m3 that emanates from the chalky and carbonic rocks of Lefka Ori.


We often take the water for granted. But only 1% of the total water in earth is available to the people for any use.
We should not forget that each use pollutes it.The proper use of water saves energy and it helps in delivering a clean environment to our children.


We all know that it is good for us, but few persons know that the reception of smaller than regular quantity of water causes many problems as light-headednesses, headaches, problems of kidneys, constipation, dehydration
Our body needs water for:
The cleaning of blood through the kidneys
The maintenance of body temperature
The digestion of foods
The transport of food and oxygen in our body
The prevention of salts accumulation in the body tissues
The removal of undesirable substances
The removal of carbon dioxide from thews


Its origin (Lefka Ori) determines its quality. It is slightly alkaline, of medium hardness, with sovereign anions the bicarbonate and sovereign cation the calcium . It has few inorganic salts and the
concentration of undesirable substances is much lower than the permissible limits. It has negligable organic charge and very good microbiological quality. Its composition make it to have an ideal
behavior in the city network.
For such a good quality the only treatment required is disinfection.


The water in order to be potable should comply with certain standards that are determined by the legislation. If it does not it should undergo suitable treatment so that it is rendered suitable. This takes place in water refineries. The water of lakes and rivers need treatment and often today so do underground waters when polluted.
The water of the resources in Agia and Miloniana complies with the standards and the only treatment needed is disinfection.
Learn more for the quality of water of our city


Disinfection takes place in Agia for the water that is distributed in the regions Pahiana, Nea Chora and city center and in Vande (where there are 3 new reservoirs of 19500 m3) for the water that goes to the central reservoir of Ag. Ioannis from where it is distributed to the remainder reservoirs and the water supply network.
The disinfectant used is sodium hypochlorite, the process is continuous, automatically monitored in 20 points in the network in order that the water reaches the consumers healthy and safe .
The disinfection is completely automated so that residual chlorine is kept constant in the network.
The disinfection with chlorine is used worldwide and because of it the aqueous infections such as cholera and typhoid fever have been eliminated in the developed countries. Today there have been developed other methods of disinfection such as ozonation, ultraviolet radiation, each one with its own advantages and disadvantages but the key difference with chlorination is that no residual disinfectant remains in the water network with the alternative methods. Thus even if somebody uses some other method of disinfection it should be followed by chlorination.
Each disinfectant, as well as the chlorination creates probably by-products when it reacts with certain substances that may exists in water.
With the new directive of EC 98/93 it is stated that the sum these by-products should not exceed the 100 μg/l (parts per billion). From the analyses that we regularly make in the water of Chania this concentration does not exceed 2μg/l. This is explained, by the fact that the water of Chania has negligable organic charge and low concentrations of chloride and bromide.


The water as it is moved in the circle of water (ground, sea, air) is enriched with various compounds. The maximum concentration of these compounds is determined by the legislation. The Greek legislation that is in effect now is KYA Y2/2600/2001(harmonised with european directive 98/83/EEC). It sets maximum permissible limits for 50 parameters and determines the minimal frequency of control.
Our water is checked daily by the laboratory of DEYACh.
We check the parameters set by the legislation, microbiological and chemical parameters in the resources and in the network in higher frequency than the requirements of directive.
The laboratory of DEYACh covers the greatest part of legislation requirements with its equipment and personnel. For certain analyses that cannot conduct with our equipment we collaborate with other accredited laboratories.
Learn more for the laboratory of DEYACh.
Learn more for the legislation on potable water.


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