See also John 4:14 but he who drinks the water I give them will in no way thirst into the age. Indeed, the water I give them will become in them a spring of water welling up to eternal life.”
and John 7:38 Whoever is believng into me, as Scripture has said, rivers of living water will flow from within them.”
One certainly receives the Holy Spirit by turning away from distrusting God and starting to trust Jesus whom God sent so that one is willing to submit to the baptism into His name that He commanded His followers to undergo. However, although God does promise to give the Holy Spirit to those who have repented and have submitted to baptism, He is free also to give the Holy Spirit before baptism, if He wills, without breaking His word. He does not say anywhere that He will give the Holy Spirit only to those who repent and get baptised.
One keeps on being watered by the Holy Spirit in real time by continuing to believe into Jesus in real time.
As one keeps on believing into Jesus the living water eventually fills the believer until His power overflows to others through the believers gifts and fruit.