THREE MAIN SOURCES OF RAW WATER
There are basically three main sources of raw water: rain water, surface water and ground water. In some areas, facilities are designed to catch rainwater. Roofs for example drain into containers to gather water for use by households. Others design their roof drainage system such that the rainwater is directed into underground or basement cisterns, where they are stored and withdrawn for household use as needed. Surface Water is found in lakes, rivers, and reservoirs while Ground water lies under the earth’s crust where it moves and seeks openings and settles in reservoirs called aquifers. Ground water in aquifers must be pumped out to the earth’s surface for use.
Consumers and end-users receive their water from two basic delivery systems: a private well or private reservoir, or a community water system. A household well pumps groundwater for own household use. The community water system may be supplied from either surface water or groundwater.
Private well or reservoir owners are solely responsible for the safety of their water supply. However, there are steps that can be taken to ensure that the well water is made safe and acceptable before use. As a first step, well owners should contact their local public health agencies for guidelines on the steps needed to be done.
Contamination can come from the water containment and surrounding human activities. As the rainwater flows into the surface reservoirs or seeps into the underground aquifers, it comes in contact with variety of matters. Water, being a very good solvent, tends to absorb things along its path, including harmful microorganisms, heavy metals, viruses, organic and inorganic chemicals, gases, etc. In the reservoir, where it comes in contact with various forms of rocks, it tends to absorb naturally occurring minerals and a variety of other substances. Some of these harmful contaminants are uranium, radium, nitrates, arsenic, chromium and fluoride.
Chemical and microbiological contamination resulting from human activities such as manufacturing, refining, agriculture, or individual misuse, almost always pose serious health risks if they find their way into drinking water. Specifically, contamination is brought about by: 1) leakages from indiscriminate handling of waste disposal, waste treatment, and waste storage sites; 2) improper handling of discharges from factories, industrial sites, or sewage treatment facilities; 3) accidental chemical and oil spills; 4) leakages from underground storage tanks; 5) improper disposal of household and shop wastes such as cleaning fluids, paint, petroleum fuels, brake fluids, motor coolants, and motor oils; 6) improper disposal of hospital wastes such as medicines, fluids, containers, surgical materials, medical packaging, etc.; 7) improper disposal of washings from non-biodegradable detergents and soaps.
The water impurities or contaminants can be summarized into the following:
Hardness, abrasiveness, odor, coloration, taste, turbidity, microorganisms, viruses, heavy metals, organic compounds, inorganic chemicals, minerals, pesticides, herbicides, biocides, fungicides, fertilizers, and disinfectants.