1 Peter 3:20-21
“...God waited in the days of Noah, while the ark was a preparing, wherein few, that is, eight souls were saved by water.
The like figure whereunto even baptism doth also now save us (not the putting away of the filth of the flesh, but the answer of a good conscience toward God,) by the resurrection of Jesus Christ:”
I believe the water mentioned in 1 Peter 3:20-21 pertains to water baptism for the following reasons:
1.The water was the means God used to carry Noah and his family to safety. The sin of the world was washed away in the flood waters. The like figure or antitype is the NT water baptism. (Acts 2:38, 22:16)
2. Notice verse 21 makes specific mention of the process having nothing to do with the removal of filth from the flesh. (This is a reference to bath water) Thus, the comment points to a spiritual transaction taking place.
3. The scripture mentions that baptism is the answer of a good conscience toward God. Our own behavior, and in this particular case getting baptized, is what prompts a good conscience. The result is to be free of guilt. God is the giver of the Holy Ghost and we have no control over that other than asking for Him to give it.
4. Lastly, the scripture specifies this is only made possible by the resurrection of Jesus Christ.