Why is the water of the Ganges sacred
According to the Puranas, the Ganges originated from the toe of Lord Vishnu.It is believed to be the water of Lord Vishnu's feet. The scriptures describe the properties of this water in the scriptures as follows:
Removal of untimely death and destruction of all diseases. Drinking Vishnu's water of feet does not lead to rebirth!
A devout Vaishnav who drinks the water of Lord Vishnu's feet is free from the fear of untimely death. All physical, mental, and spiritual ailments are easily eradicated. After leaving his mortal body, he is liberated from the cycle of birth and death and resides in the abode of Lord Vishnu, becoming Vishnu himself.
Bhagiratha compelled the heavenly Ganges to descend through rigorous penance for the salvation of his ancestors. Sagara's sons, who had been reduced to ashes by the sage's anger, were saved by the touch of Bhagirathi.
To physically test the purity and speciality of Ganga water, bring its water and keep it in a vessel, insects will not fall in it. The reason? Ganga coming from Gomukh keeps on absorbing the essence of various minerals and herbs found on its way. In this way, the ordinary looking Ganga water becomes like nectar. It is full of divine medicinal properties.
Two-four drops of Ganga water can infuse life even in the dead. That is why there is a tradition among Hindus to pour Ganga water in the mouth of the dead. So that the deceased reaches the divine worlds while remembering his deity in his conscious state.