Water is the most essential natural resource on Earth. It covers about 71% of the planet’s surface and is vital for human survival, agriculture, industries, and ecosystems.

Chemical Composition

Water is a chemical compound made up of two hydrogen atoms and one oxygen atom (H₂O). Its unique molecular structure gives it remarkable properties such as:

• High heat capacity

• Excellent solvent ability

• Surface tension

• Cohesion and adhesion

These properties make water essential for biological and industrial processes.

Sources of Water

Water is obtained from various natural sources:

• Surface water (rivers, lakes, ponds)

• Groundwater (wells, boreholes)

• Rainwater

• Seawater

Water Quality Parameters

Water quality is determined by physical, chemical, and biological characteristics:

Physical:

• Color

• Odor

• Turbidity

• Temperature

Chemical:

• pH

• Hardness

• Dissolved oxygen

• Total Dissolved Solids (TDS)

Biological:

• Bacteria

• Viruses

• Microorganisms

Understanding these basics helps in identifying the need for water treatment.