Risk analysis in drinking water accumulation

Drinking water is safe water, from the perspective of long-term use is does not cause any disease, pathogenic and hygienically unsafe microorganisms do not spread in it and customers enjoy its consumption. Drinking water is regarded as a foodstuff, therefore the known HACCP system can be used in the control system which can be applied not only directly to the final product, but also to the whole system of drinking water production, distribution, and accumulation. Even if there is no problem concerning the water processing and the technological line is well adjusted, the quality of drinking water is subsequently deteriorated by its transportation and accumulation. The condition and character of the operated distribution network and reservoirs are significantly and substantially related to the maintenance of the biological stability and quality of drinking water. This is well confirmed by biological audits of the distribution networks and water reservoirs. A significant fact is the negative influence of the secondary contamination by air in the reservoir facilities and the occurrence of microorganisms (fungi, bacteria) in free water and in biofilms. The findings obtained in the framework of biological audits were so alarming that the outputs of biological audits contributed to the reconsideration of the efficiency of the standard for the construction and design of water reservoirs and pointed out the necessity of its review.