what is good drinking water?
So, what qualities constitute “Good” drinking water?
People judge water mainly by its taste, its appearance and particularly its smell. If the water is assessed as tasteless, colourless and odourless it is often thought to be “pure” - but clear, good tasting water is not necessarily a guarantee that it is safe to drink. A whole range of additional qualities such as acidity or alkalinity, Total Dissolved Solids (TDS) content, hardness and particularly bacteriological content are required to more accurately assess true water quality.
Taste and Smell
Are strongly related. Unpleasant odours and flavours can arise from decaying organic matter and chemicals such as chlorine (and its by-products) which have been used to make the water “safe”. Traces of undesirable aromatic fertilizers and pesticides may also be present from agricultural run-offs.
Colour and Turbidity
Are also related in that they affect the appearance of the water sample and both can derive from the presence of chemicals and muddy sediments. Turbidity is the lack of clarity due to very fine particles of solid matter and gas held in solution, possibly originating from eroding soils and decaying vegetable matter.
pH
Is a unit which indicates the acidity or alkalinity of a solution. (Scientifically, it is defined relative to the Hydrogen Ion Concentration of the solution.) When the pH=7 it means that a solution is “neutral”, pH less than 7 means that the solution is acidic and may cause corrosion which releases metals into the solution, when the pH is greater than 7 (up to a maximum of 14) means that the solution is alkaline and may form scale in pipes and equipment. Exposure to water with pH greater than about 9.5 can cause skin irritations and this water will taste bitter. pH values can be decreased by chlorination of water supplies while they can be increased by lime leached from cocrete tanks and pipes.
Water with a pH in the range 6.5 – 7.5 is generally considered acceptable for drinking purposes.
