See the below verses that talk about the blood of Jesus. It's pretty clear. Only the blood of Jesus can cleanse from sin. But if we walk in the light, as he is in the light, we have fellowship one with another, and the blood of Jesus Christ his Son cleanseth us from all sin. All who have received the Lord Jesus Christ as their personal Saviour may be water baptized.
Water baptism is only for saved people.
A person is only baptized after salvation has already occurred in his life. After salvation, as an act of obedience and as a outward testimony of the inward conversion, a person is water baptized. There are no regenerative effects at all be getting water baptized. Salvation, the new creation, the infilling and sealing of the Holy Spirit all occurred at the moment of salvation. The answer is simple.