Humans need a clean ground water for consumption. But, not all decent spring consumed, due to its nature and its contents are always different. The best source of drinking water is the source of water contained in the volcanic mountain.

"The best source of drinking water comes from mountain springs of volcanic origin in the ground water. It is based on scientific explanation that the volcanic mountain spring water is relatively free of pollution, containing a natural mineral that is balanced and meets the three conditions characteristic of a good source of ground water," said Prof. Dr. Sari Bahagiarti, MSc., hydrogeological experts from UPN Veteran Yogyakarta, in the event Anugerah Abikarya Syandana 'Water is a natural goodness and benefits for the body' in the House of Imam Bondjol, Menteng, Jakarta.

Prof. Sari explained that the three conditions characteristic of a good source of ground water is the quality, quantity and continuity. In terms of quality, meaning that the source of drinking water meets the standards of three measurements, the physical properties, chemical and biological.
From the physical aspect, the source of drinking water should not be colorless, odorless, tasteless and turbid. From the aspect of chemistry, materials drinking water should not contain heavy metals (eg mercury, nickel, lead, zinc and silver), or toxic substances such as hydrocarbons and detergents.

While the biological aspects, drinking water should not contain microbes, especially Entamoeba coli bacteria.

"In addition, the volcanic mountain water sources are usually found in ground water layer is not affected in the dry season or rainy season. Layers of ground water will not have a relationship with surface water," explained Prof. Sari.

From the quantitative side, continued Prof. Sari, volcanic mountain spring water originating from ground water also has a reserve of water in a very large, so that usually appears as artesian springs.

In terms of continuity, with normal rainfall and green environment in mountainous areas, the sustainability of water resources in mountain areas can be maintained.

Prof. Sari also added that the mountain springs are naturally formed from rain water into the system terinfiltrasi layers of volcanic rocks from the force of gravity.

"In the journey through the layers of volcanic rock, rain water is filtered and absorb the minerals essential to human body naturally, such as calcium, sodium, magnesium and potassium. The process naturally produces water with a naturally balanced mineral content," explained Prof. Sari further.

Then what is the impact if the volcanic mountain has erupted?

"The mountain began to actively clear volcanic influence in the surrounding water sources. From our study of post eruption of Merapi in 2006, there were changes in water content. Not only the mineral content, but also fluorescent, which can harm health. But this content will be back to normal after several time. For Merapi eruption yesterday, we do not have the data, because the research is underway, "explained Prof. Sari.