The water distributed by EMATSA favourably exceeds the health criteria established by the competent health authorities as well as those established by the World Health Organization and the European Union, as established in the 140/2003 Royal Decree of 7 February, establishing the health criteria of quality drinking water.

Chlorine is the most commonly used water disinfectant in the world for its effectiveness and dependability to eliminate any harmful microbes that water supply pipes or storage tanks may contain. The chlorine added to drinking water for human consumption is a minimum health guarantee – set by law – which is not harmful to people’s health.

Because it is the method that best guarantees water disinfection until it reaches consumers’ taps, preventing pathogens from proliferating in storage tanks and supply lines, and has more than proven its safety in the concentrations used . This is why the World Health Organization recommends it as the most appropriate disinfectant for water.

The World Health Organization states that, in the concentrations established by legislation, chlorine is completely harmless to health. Maximum concentrations of this compound in tap water established by this organization ensures that there is no risk to health.

In fact, the chlorination of drinking water is one of the most significant advances in the protection of public health, due to its high lethality against bacteria and other microorganisms. It has helped to prevent and eradicate many waterborne diseases. The presence of a correct dose of chlorinated water after treatment entails no risk whatsoever to health and confers it the effect of protection from contamination as well as being an indicator of its correct disinfection.

Under current state regulations (Royal Decree 140/2003) and the transposition of the 98/83/EC European Directive, the concentration of chlorine in drinking water should not exceed 1 mg./l., although this is an indicative parameter. Although state law sets no minimum value for free chlorine, different regions have established, through their monitoring plans, and in most cases, a value of 0.2 mg./l.

Taking into account that chlorine disappears in function of time spent in the water and its temperature, among other factors, its level is monitored throughout the distribution network. Therefore, during the journey to consumers’ households, if the level of this component is below the indicative established threshold, small amounts of chlorine (re-chlorations) are administered to ensure the quality of water from the distribution network itself.