Water baptism in Jesus Name is a vital PART of the new birth, just like faith, repentance and the Spirit. Leave out a part (any part) and you do not have a complete NT new birth experience. No complete NT new birth experience and the person is lost.
Joh 3:5 Jesus answered, Verily, verily, I say unto thee, Except a man be born of water and of the Spirit, he cannot enter into the kingdom of God.