Organoleptic parameters
Colour
Normally water is colorless. However, tt may have a color in some conditions (such as the presence of chemicals).
Turbidity
Turbidity measures the water cloudiness, i.e. how clearly one can see through the water.
Odor
Plain water is oderles, but sometimes substances (like chlorine) present in the water do give it an odor.
Taste
The taste of the water depends on its content. Water taste is monitored to guarantee a gustative quality to the customer.
Physico-chemical parameters
pH
The pH of water measures the activity of its hydrogen ions.
The pH of absolutely pure water at 25°C is 7.
Natural water contain minerals and dissolved gases and its pH may not be 7. Usually natural surface waters have a pH between 6 to 8.5.
Chloride
Chloride is predominant anion in sea water and in many freshwaters.
Chloride salts are highly soluble and tend to stay dissolved.
Chloride concentrations vary from 1 mg/L in streams in humid areas to more than 100,000 mg/L in waters in arid areas.
Alkalinity
Alkalinity measures the capacity of the water to neutralize acid.
Alkalinity in natural waters is usually caused by the presence of bicarbonate and carbonate ions, and less significantly by hydroxide and acid radicals like borates, phosphates and silicates.
Total hardness
Water hardness naturally results from a solution of calcium and magnesium (and sometimes of other polyvalent metals). Excessive water hardness causes incrustations on cooking utensils and water heaters, and increases the consumption of soap or detergent.
Undesirable substances
Nitrate
Nitrate is the most stable form of nitrogen (N) in water in an oxidizing environment and is usually the dominant form of nitrogen in natural waters. Very high nitrate concentration presents a risk for bottle-fed infants.
Ammonia
Ammonia is another form of nitrogen (see Nitrates). High concentration of ammonia usually indicates pollution.
C.O.D.
C.O.D. (Chemical Oxygen Demand) measures the quantity of reductive substances which can be oxidized by KMnO 4 in given conditions. It helps identifying the organic contents in the analyzed water.
Iron
Iron is an abundant and widespread consituent of rocks and soils. Iron concentrations in natural waters depends on mutiple chemical processes (oxydation and reduction, precipitation and solution of hydroxides, carbonates and sulfites, etc). Too much iron in the water affects its taste and may leave stains on clothes.
Residual Chlorine
The use of chlorine during water treatment is necessary to eliminate any biological contamination of the potable water. Chlorine is added into the water during the treatment, and then its concentration naturally decreases as water flows through the water network. Residual chlorine is the quantity of chlorine present in the tap water.
