When I grew up playing golf, one of the first things I learned on an actual golf course was that I couldn't ground my club in a water hazard. It didn't matter if it was a lateral water hazard or a regular water hazard. It didn't matter if the ball was in grass in a water hazard or in the water. You couldn't ground your club.
But under the new golf rules debuting in 2019, those days are no more. A golfer will be able to ground their club in any hazard.
It's not a hazard anymore
There's one caveat to the new golf rules allowing a golfer to ground their club in a hazard. It's not called a hazard anymore. It's not called a water hazard. It's now called a penalty area. The USGA and R&A gave a new name for water hazards because they're also allowing courses and tournament operators to declare more portions of the golf course to be like a water hazard. Now, forests, jungles, lava rocks, desert and more can be declared a penalty area.
With the expansion of penalty areas and the desire to speed up play, that means golfers will be in penalty areas where it just makes sense to be able to ground a club. Instead, then, of creating tiers and types of penalty areas where grounding is allowed or prohibited, the USGA and R&A decided a player can ground a club in a penalty area without issue. Golfers are also now allowed to remove loose impediments and touch loose impediments in penalty areas, erstwhile hazards.
Why penalty areas exist
The USGA and R&A have made it clear penalty areas exist not to penalize golfers, rather to give golfers options when they're in a situation where it's not practical or possible to hit a golf ball where it lands. Penalty areas are there to give golfers options for relief, allow them to continue playing and move on with the round. By allowing a golfer to ground their club in a hazard or penalty area, the USGA and R&A are still allowing penalty areas to serve their purpose without being unnecessarily penal to a golfer.