The domestic dessedentao, uses and public uses of the water if relate to those demands that are supplied by systems of water supply. These systems are dimensionados to take care of to the demands that directly depend on the population to be taken care of. The demographic projection determines the estimate of the demand. The suppliment can be carried through from superficial sources, underground rivers or lakes (reservoirs), or sources (water-bearing). In the case of rivers, as the fluvial regimen is changeable, the critical conditions of supplying will appear in the estiagem station. When frequently unacceptable the quantitative water availability in the captation section will be inferior to the suppliment demand, could be constructed a reservoir of regularization. Its objective will be to store guadurante the humid station of way to form hdricas reserves that will complement the availabilities during the dry station. The water-bearing underground are natural reserves that practically present constant quantitative availability, when not submitted to the one on-explotao.
This term assigns the situation where if it extracts more water of a water-bearing subterranean that its natural recharge, what it causes to its degradation and reduction of quantitative availability. Tests of bombardment will be able to establish adequate taxes of extration. The standards of quality for systems of water supply are very demanding what it determines, in general, the treatment of waters in stations of water treatment (ETA) previously to its distributions and consumption. The underground waters can offer a qualitatively more adequate alternative. The underground pollution is more easily prevented water-bearing of what of rivers or lakes, even so in the despoluio of these sources occurs accurately the opposite. From there the strategical necessity of protection of the water-bearing underground, as hdrica reserve for the future generations, activity that the biggest relevance in industrialized regions and with demographic high-density has assumed, that high demand presents, increased of high potential of pollution.