Back on the line: where do you drop?

Your ball lands in the stream, in a yellow penalty area. For one penalty stroke you take back-on-the-line relief: the line runs from the flag through the crossing point, the spot where your ball last crossed the edge of the penalty area, and as far back as you like (Rule 17.1d).

How far back?

That is up to you. A rangefinder helps you find the spot with your favourite distance to the flag. That has been allowed since 2019, unless a Local Rule prohibits it (Rule 4.3a).

Since 2023: land on the line

You drop the ball on the line, and it must also land on the line (Rule 14.3b). If it lands beside it, the drop was not made in the right way: you drop again, and that attempt does not count. From 2019 to 2022 you could drop within one club-length of a point on the line, so also beside it.

One club-length in any direction

The spot where the ball lands sets the relief area: one club-length in any direction, even towards the hole. It just must not come to rest nearer the hole than the crossing point, and it must stay in the same area of the course where it landed (Rule 17.1d).

If it rolls further, you drop again. If it rolls too far again, you place it on the spot where it first touched the ground on the second drop (Rule 14.3c), as in the video Lateral drop.