It is essential to know where tap water comes from and how to use it safely for purposes other than drinking. Germs or bacteria like to grow in puddle (not flowing). Most tap waters are not sterile; therefore, germs or bacteria can accumulate. Although public water systems are functioning properly, small amounts of bacteria will grow naturally in surroundings. When these bacteria occupy the building or house pipes, they can grow and multiply if the conditions are possible. This could happen, for example, if the faucet has not been used for a long time and there is residual water in the pipes.

Germs and chemicals can contaminate drinking water into water sources or distribution systems after the water has been treated. Harmful germs and chemicals contaminate water from a variety of sources such as;

1. Fertilizers, pesticides, or other chemicals that have been applied to area near water

2. Concentrated feeding operations (large industrial animal farms)

3. Manufacturing operations

4. overflown overflow

5. storm water

6. Wildlife

7. Rocks and soils that naturally contain chemicals and minerals, such as; arsenic, radon, and uranium

8. Cracks in water pipes or other distribution system problems

Most people probably know that ingesting harmful water bacteria can cause stomach disorders such as vomiting and diarrhea. However, these bacteria can also cause damage to the lungs, brain, eyes, or skin. Running the water for a while before use can keep bacteria out of faucets, showers, or other water sources, especially if the residual water has been in the pipes longer than usual (for example, for a week or more).

Here are some steps to protect from bacteria in the house water tap:

1. Rinse the faucet and shower if they are used infrequently.

2. Clean, disinfect and maintain all equipment that uses water

3. Contact the water supplier about the water quality to keep private water sources safe.

There are several types of household water treatment systems that are most commonly used:

1. A filtration system is a device that removes contaminants from water through a physical, chemical, and/or biological barrier process.
2. A water softener is a device that reduces the hardness of water.
3. Water softeners usually use sodium or potassium ions to replace calcium and magnesium ions, the ions that create “hardness”.
4. Distillation system is the process of boiling impure water, collecting steam and condensing it in another container, leaving a lot of solid impurities.
5. Disinfection is a physical or chemical process that inactivates or kills pathogenic microorganisms. Examples of chemical disinfectants are chlorine, chlorine dioxide and ozone. Examples of physical disinfectants include UV light, electron radiation, and heat.

Source : www.cdc.gov