Here lies one whose name was writ in water

What's the meaning of the phrase 'Here lies one whose name was writ in water'?

Fame, and indeed life, is fleeting.

What's the origin of the phrase 'Here lies one whose name was writ in water'?

A version of the words originate from Beaumont and Fletcher's play Philaster, 1611:

"All your better deeds Shall be in water writ, but this in Marble."

In the better known form 'writ in water' they appeared in Keat's Poetic Works, 1821.

'Here lies one...'. The 'here' in question is Rome.
Keats travelled to Rome and died there, aged just 25, in February, 1821. He told his friend Joseph Severn that he didn't want his name to appear on his tombstone, but merely this line:

"Here lies one whose name was writ in water."

Severn honoured that wish, as the gravestone shows - Keats is commemorated just as 'A young English poet'.

Keats's Grave - New Protestant Cemetery, Rome

THIS GRAVE CONTAINS ALL THAT WAS MORTAL OF A YOUNG ENGLISH POET WHO ON HIS DEATH-BED IN THE BITTERNESS OF HIS HEART at the malicious power of his enemies desired these words to be engraved on his tomstone "HERE LIES ONE WHOSE NAME WAS WRIT IN WATER" FEB 24 1821

See also - season of mists and mellow fruitfulness.