From on the green, I accidentally putted my ball off the green and down into a water hazard. I know I'm allowed to take relief from the hazard and play from the same spot with a one-stroke penalty. However, was I supposed to drop or place the ball on the putting green?
--- Jerry, Myrtle Beach
Jerry, you're correct that the first option under Rule 26-1 - Relief for Ball in Water Hazard allows you to play a ball as nearly as possible at the spot from which the original ball was last played. This Rule next instructs us to reference Rule 20-5 - Making Next Stroke from Where Previous Stroke Made.
It reads, "When a player elects or is required to make his next stroke from where a previous stroke was made, he must proceed as follows:(a) On the Teeing Ground: The ball to be played must be played from within the teeing ground. It may be played from anywhere within the teeing ground and may be teed.(b) Through the Green: The ball to be played must be dropped and when dropped must first strike a part of the course through the green. (c) In a Hazard: The ball to be played must be dropped and when dropped must first strike a part of the course in the hazard. (d) On the Putting Green: The ball to be played must be placed on the putting green."
For your situation, option 'd' gives us the answer. The ball should have been placed.
Sorry to hear of your putting mishap. I hope you made the next one for an interesting two-putt.