Bhagawat Purana mentions that the water of Ganges carries the blessings of Lord Vishnu’s feet; hence Mother Ganges is also known as Vishnupadi

Bhagawat Purana mentions that the water of Ganges carries the blessings of Lord Vishnu’s feet; hence Mother Ganges is also known as Vishnupadi, which means “Emanating from the Lotus feet of Sri Vishnu.”, Because Maa Ganges directly touches the lotus feet of Lord Vishnu before descending within this universe. It finally settles in Brahmaloka, abode of Lord Brahma before descending on Earth at the request of Bhagiratha and held safely by Lord Shiva on his head to prevent destruction of Mother Earth. Then, the river Ganges was released from Lord Shiva 's matted hair to meet the needs of the country. Ganga represent purity, mental ,physical. ‪Lord Shiva holds Ganga, the purity with jata which is symbol of renunciation from worldly impurities. So purity can only achieved by renunciation. Holding Maa Ganga in his matted hair, Hence Gangadharaya his name. Shiva holding Ganga in head means purity is first virtue to hold. He not only holds Ganga but also Ganga flows from his head, it mean that we must have to spread purity among others also! Har Har Gange ~ Har Har Mahadev !!!!