There, the water is stored in boxes d? water. It is in this stage that can occur the contamination. Also the springs, mines and watering holes, that they are water suppliment sources, can present contamination, either for if locating in the proximity of fossas, where it has great presence of organic substance, or for the access of animals, rain water or other sources of contamination and pollution. These sources can be classified of three forms: Prompt sources of pollution: They are the ones that reach the water-bearing one through a point. Examples: sumidouros of domestic, common sewers in agricultural communities, aterros sanitary, emptyings of deposits of chemical products, chemical emptyings of transporting ducts of domestic sewers or products. These sources are responsible for pollutions highly concentrated in the form of pens. Linear sources of pollution: They are provoked for the infiltration of superficial waters of rivers and the contaminated canals.
' ' The possibility of this pollution to occur will depend on the direction of existing hydraulical flow between course d? water and water-bearing subjacente.' ' It is necessary to emphasize that, throughout one exactly course, has places where the flow if of the one of water-bearing for talvegue and the others where if it passes the inverse one, that is, the waters of the river if they infiltrate in direction to the water-bearing one. The existence of deep wells in functioning in the neighborhoods of course d? water will be able to force the water infiltration contaminated in the water-bearing one being inverted its flow or increasing its speed. Diffuse sources of pollution: They are the ones that contaminate extensive areas. Normally the pollutants carried for aerial chains must, rain and for the agricultural activity. In urban accumulations, where it does not have net of sanitary exhaustion, fossas septic and sumidouros in such a way is regularly spaced that the set finishes for being a diffuse source of pollution.