The careful reader will note that the water is not an analogy because it is the bath or washing of water with the word or utterance.No, it doesn't.
Read it carefully. It's the Word that washes. The water is only an analogy.
According to the context that is a different kind of clean, they are pruned in order that they may bear more fruit. Here is that passage in the Green's Literal Translation, "Every branch in Me not bearing fruit, He takes it away; and each one bearing fruit, He prunes, so that it may bear more fruit. You are already pruned because of the Word which I have spoken to you." John 15:2-3 -LITVThat's why we have verses like:
You are already clean because of the word I have spoken to you. - John 15:3
It is this word which testifies that He sanctifies and cleanses by the bath or washing of water with the word or utterance. Listen to the truth of His wordSanctify them by the truth; Your word is truth - .John 17:18