What are the impurities found in tap water?

Water in nature is regarded throughout the world as being totally 'pure', despite the fact that that is far from the truth. Even if a body of water is totally detached from any possible source of contamination from water flowing into it from rivers and streams, it will invariably be found to contain some form of chemicals and minerals because water is such a good solvent.

These chemicals can be drawn into the water by minerals and gases in the air, or eroded from the soil or rock. The integration of these dissolved materials are regarded as the ingredients that give water its title of 'pure water', which is actually a contradiction in terms, as water containing any form of foreign bodies, no matter how molecular can never be described as totally 'pure'.

The impurities that are found in water to give it its particular taste as well as causing such effects as hardness, caused by the presence of calcium or magnesium, colour, which is caused by the presence of iron in the water, going as far as possible poisoning caused by high concentrations of arsenic in the water or even radioactivity caused by the presence of radium.

Apart from these natural impurities that can gradually dissolve into water from its natural surroundings. There are also a number of forms of man-made contamination that can find their way into water. The most common are fertilisers and pesticides that can flow into water through overuse by the agricultural industry as well as toxic wastes from heavy industry.

On certain occasions, human effluent can leak into water systems through a fault in a sewage disposal system, However, and very thankfully, these occasions are few and far between.


The most common mineral impurities found in tap water are:

• Aluminum - Leached from the soil

• Arsenic - Leached from the soil

• Calcium - Leached from the soil

• Chlorine - Added as a disinfectant

• Copper - Leached from pipes

• Fluoride - Sometimes added for dental health

• Lead - Leached from underground pipes,

• Nitrates - Leached from the soil

• Phosphates - Leached from the soil/Agriculture

• Radium - From the breakdown of Radium-containing rocks

• Sodium - - Leached from the soil/seawater


These are just a few of the more than 250 impurities that can be found in tap water. However in day-to-day life tap water in most developed regions of the world undergoes fairly high levels of filtration, and after which chlorine is introduced into the water in very low concentrations, making it suitable to use for most domestic applications. Water that has undergone a regular filtration process is known as potable water and can be drunk from the tap without excessive danger to health. But in truth potable water is best used for just about every other task in a family home, such as washing the car, flushing the toilet watering the plants washing the dishes and taking a shower.

Relatively speaking, tap water is inexpensive, much less than natural bottled waters that come from fresh streams usually underwater and undergo extensive filtration, or distilled water is generally used only in industry or in certain very specific domestic applications, in hospitals or scientific research, where water has to be as close to 100% pure as is possible