Water gets contaminated by the addition of :
(i) Agricultural chemicals:
Farmers use excessive amounts of pesticides and fertilizers to increase the crop production. These chemicals get carried away to the water bodies due to floods which lead to water pollution.
(ii) Industrial wastes:
Industries release harmful chemical wastes into water sources without treating those chemicals which results in water pollution.
(iii) Sewage wastes:
Waste materials from kitchens, toilets, and laundry sources are also responsible for contaminating water bodies.