(Revised) Is this Homebrew cantrip balanced? Water beam [duplicate]

here is a link to the original draft. I was inspired to make this by the decanter of endless water item. I want an opinion on the balance of this spell.

1d4 force damage

Casting time: 1 action

Range: 30 feet

Duration: instantaneous

Components: V, S Classes that know: wizard, sorcerer, druid

The user shoots a beam of water at one target within range. The target must make a strength saving throw equal to the users spell dc. On a failure the target takes 1d4 force damage and is knocked prone. On a successful save, the target takes half the damage (rounded down with a minimum of 1) and isn’t knocked prone.

At higher levels this spell increases in damage. Lvl 5 (2d4) lvl 9 (3d4) lvl 13 (4d4) lvl 17 (5d4)