Valmiki Ramayana Aranya Kanda Sarga 16 Shloka 25

तुषारपतनाच्चैव due to snowfall, भास्करस्य Sun's, मृदुत्वात् owing to mildness, शैत्यात् caused by coldness, रसवत् tasty, जलम् water, अगाग्रस्थमपि although flowing from top of the mountain, प्रायेण generally.

Due to snowfall, mildness of the Sun, and coldness (of weather) even the water flowing from the mountain top is not generally tasty.