FEATURES OF WATER                                                                                                                                          
water is a polar inorganic compound that is at room temperature a tasteless and odourless liquid , which is nearly colorless apart from an inherent hint of blue.
water has three different types of features namely: chemical, biological and physical features.
physical features
These  features include :temperature, colour, taste, odour etc.
These features are determined by senses of touch, sight, smell and taste. for example temperature by touch, colour , floating debris, turbidity and suspended solids by sight and taste and odour by smell.
Turbidity. Is a measure of the light-transmitting features of water and is comprised of suspended and colloidal material . It is important for health and aesthetic reasons. Transparency of natural water bodies is affected by human activity , decaying plant matter, algae blooms , suspended sediments and plant nutrients.
Temperature; is a basic water quality variable . It determines the suitability of water for  various form of aquatic life .
Temperature affects a number of water quality parameters such as dissolved oxygen which is a chemical feature. Oxygen solubility is less in warm water than cold water.
Temperature in water bodies generally follows mean daily air temperature. It influences: amount of oxygen that can be dissolved in water, rate of photosynthesis by algae and other aquatic plants, metabolic rates of organisms, sensitivity of organisms to toxic wastes, parasites and diseases, and timing of reproduction, migration, and aestivation of aquatic organisms.
Color
Color in water is primarily a concern of water quality for aesthetic reason. Colored water give the appearance of being unfit to drink, even though the water maybe perfectly safe for public use. Color of the water body can indicate the presence of organic substances, such as algae or humic compounds. Determination of color can help in estimating the costs related to discoloration of the water. Color is reduced or removed from water through the use of coagulation, settling and filtration techniques.
Taste and odour;  Taste  and odour are human perceptions of water quality. Human perception of taste include; sour(hydrochloric acid) salty(sodium chloride), sweet(sucrose) and bitter(caffeine) 
Odour is produced by gas production due to the decomposition of organic matter or by substances added to the wastewater . 
Solids
Total dissolved solids(TDS) is the term used to describe the inorganic salts and small amounts of organic matter present in solution in water. The principle constituents are usually calcium, magnisium, sodium and potassium cations and carbonate, hydrogen carbonate, chloride, sulfate and nitrate anions.
Chemical features
There are few chemical constituents of water that can lead to health problems resulting from even a single exposure. An appreciable number of serious health concerns may occur as a result of the chemical contamination of drinking-water . The major chemical features of the water are discussed below: 
•	pH: is a measure of how acidic or basic (alkaline) the water is. It is defined as the negative log of the hydrogen ion concentration. Changes in pH may alter the concentrations of other substances in water to a more toxic from. Ammonia toxicity chlorine disinfection efficiency and metal solubility are all subjective to change in pH.
•	Electrical conductivity; The conductivity of water is an expression of its ability to conduct an electric current as a result of breakdown of dissolved solids into positively and negatively charged ions. The positive ions are potassium, sodium, calcium and magnesium. The negative charged ions in water include sulfate, carbonate, bicarbonate, nitrates and phosphates.
•	Salinity; salinity is the measure of amount of salt in water .The presence of high salt content may make water unsuitable for domestic ,agricultural or industrial use.
•	Alkalinity; The alkalinity of natural water is  generally due to the presence of bicarbonate formed in reaction in the soil through which the water percolates.it is a measure o the capacity the water to neutralize acid and it reflects its buffer capacity.it may also be attributed to the presence of carbonates and hydroxides.
Hardness: Is a natural feature of water which can enhance its palatability and consumer acceptability for drinking purpose. The hardness of water is due to the presence of calcium and magnesium minerals that are naturally present in the water .The common signs of hard water supply are poor lathering of soaps and scum. The hardness is made up of two parts; temporary(carbonate) and permanent(non carbonates) hardness. The temporary hardness of water can easily be removed by boiling the water
Biological features
•	Microbial contamination; is one of the major concerns of water quality. Many types of microorganisms are naturally present in the water such as protozoans, amoeba, cryptosporidium and giardia.