(𝐢) It should be clear and colourless.
(𝐢𝐢) It must not be foul-smelling.
(𝐢𝐢𝐢) It must have sufficient amount of oxygen dissolved in it.
(𝐢𝐯) It should be free from harmful microorganisms.
(𝐯) It must also be free from various chemical pollutants that are injurious to our health.