This is a very important message for those who do not know God., page-223

"What is the water representation in this verse?"

In short = the word of God and the messages from it which come from Jesus, as he was raised in the word by the father, given it, with a Key emphasis of setting the records straight, as in utter most Truths.
You may or may not be aware, but this passage is linked to a number of Jesus's messages, namely the Spirit of truth, Comforter, where we would all be taught by the God and Father (the Comforter) who would take all of Jesus's words and show and teach you, resulting in;

Keep in mind for the following, the word of God is deemed as Spirit.
John 7:38, 39 - He who believes in Me, as the Scripture has said, out of his heart will flow rivers of living water.” = (The word of God).
But this He spoke concerning the Spirit, whom those believing in Him would receive; for the Holy Spirit was not yet given, because Jesus was not yet glorified.

(John 16:14 - He shall glorify me: for he shall receive of mine, and shall shew it unto you.)
Hmmm, guess WHO glorified Jesus = The Father who is the Spirit of Truth = Comforter = The Holy Spirit,

"How does it relate to the Samaritan Woman?"

First up, if you read the surrounding passages, you would have noticed a Key point that Jesus highlighted, with regards to what the woman said, or her actions and that being, How Truthful she was = TRUTH setting the stage here.

She would drink the water = word of the Fathers from Jesus and rivers of life (words) would flow from her and whether others drink it, is another matter lol.

Jesus said to her, “Woman, believe Me, the hour is coming when you will neither on this mountain, nor in Jerusalem, worship the Father.
You worship what you do not know; we know what we worship, for salvation is of the Jews.
But the hour is coming, and now is, when the true worshipers will worship the Father in spirit and truth; for the Father is seeking such to worship Him.
God is Spirit (the Holy), and those who worship Him must worship in spirit and truth.”
The woman said to Him, “I know that Messiah is coming” (who is called Christ). “When He comes, He will tell us all things.”= (The water that he will give, gave, words of the Fathers, Spirit and Life).

Are you noticing the emphasis being put on the word Truth here?
And -> "You worship what you don't know"?

John 17:3 - This now is the eternal life that they should know You, the Only TRUE God and whom you have sent, Jesus Christ.

Unquestionably here, Jesus independently of himself, defines the Father as the only true God when he was here.

1. You have said or implied, one can get away with blaspheming the Son or the Father but NOT the Holy Spirit.
2. Is your Holy Sprit person greater than them or why is this the case ?
3. If that be the case, WHY did Jesus not mention that one also needs to know your Holy Spirit person as well as him and the Father, for eternal life ????????
4. Can You provide a Bible verse that says, you need to know your Holy Spirit person, to obtain eternal life ?
5. If there is not such verse, WHAT does that tell you, or why wouldn't there be one ?
--------------
"There's no water in you welling up to eternal life. Just unrepentent words of accusations."

Are you condemning me for doing the following ?
1 John 4:1 - Beloved, do not believe every spirit, but test the spirits, whether they are of God; because many false prophets have gone out into the world.

How do we test = test peoples words, as they are deemed as the spirit of them, their spirit person expressed.