The two main hazards on a golf course are water and sand.
You may never "ground your club" in a hazard.
This means you may not allow your clubhead to touch the ground before striking the ball.
If you do you will incur a two-stroke penalty.
You must also not:
RED WATER HAZARD
Red stakes are used to mark a lateral water hazard.
This can be exactly the same as a normal water hazard - and in some cases may be a different stretch of the same stream.
But instead of running across a hole, a lateral water hazard runs towards it.
Because of this it is not possible to drop the ball behind the water in the same way for a normal water hazard.
The rules for playing and dropping the ball are the same as for the normal water hazard except in one regard.
A player can drop a ball within two clubs lengths of where the ball crossed the hazard on either side of the ditch as long as it is no nearer the hole.
YELLOW WATER HAZARD
A normal water hazard is marked by yellow stakes.
The stakes are movable obstructions so if they interfere with the ball or your stance you can usually move them without penalty.
The entire area of the ditch between the yellow stakes is deemed to be the hazard, not just the water.
So even if your ball lands on the bank, you may still not ground your club or remove twigs etc.
If the ball is lying in the water you may attempt to play it, but may not use any artificial aid to help your stance - although you can take off your shoes and socks!
If you decide not to play the ball or have reasonable evidence the ball is lost in the hazard, you may either:
ETIQUETTE