Water Walls

The Water Walls is an obstacle, firstly introduced as the sixth and final obstacle in Stage Two on American Ninja Warrior 10, replacing the Wall Flip from the past two American Ninja Warrior season.

It consisted of a swimming tank, separated by three Plexiglas-made walls. Each wall had a door placed in the water and each door operated differently, as:
 * the first door required the competitors to slide it to the left,
 * the second door required the competitors to lift it up, and
 * the third door required the competitors to to open it up by cranking a valve in a clockwise direction.

Competitors must swim and dive into the pool and get through the doors to reach the buzzer at the end of the pool.

The obstacle ended up defeating one competitor, Najee Richardson, when he timed out soon before reaching the buzzer.

American Ninja Warrior 11
On American Ninja Warrior 11, the Water Walls returned as the sixth and final obstacle in Stage Two.

This time, more competitors could reach this obstacle and similarly to the previous season, only one competitor, Flip Rodriguez, failed after timing up from a slow pace throughout the stage.

On American Ninja Warrior 13, the obstacle is replaced by the Falling Shelves.

Australian Ninja Warrior 5
On Australian Ninja Warrior 5, the Water Walls appeared as the ninth and final obstacle in Stage One. The obstacle was renamed as the Underwater Escape, and featured a few changes compared to its appearance on American Ninja Warrior:
 * The first and third doors weighed 32 kilograms, while the second door weighed 36 kilograms.
 * The third door required competitors to slide it to the left, making it similar in function to the first door.

During the broadcast, only one competitor, Travis Edwards, timed out there, but many competitors showed signs of struggle when attempting the obstacle.

Competitors' Success Rate

 * All results based on the NBC broadcast and external information found

Trivia

 * The Water Walls was the first obstacle in American Ninja Warrior history that allowed the competitors to touch the water to progress. However, compared to any SASUKE/Ninja Warrior competition globally, the obstacle was the second obstacle to do so (after the Backstream from SASUKE).
 * Most notably, both water obstacles have been attempted and completed by Drew Drechsel. Drechsel's experience with the Backstream beforehand had actually given him experience with attempting the Water Walls.
 * The Water Walls on American Ninja Warrior 10 became the first instance in American Ninja Warrior history where the final obstacle of Stage Two defeated a competitor (since the national finals/Mount Midoriyama course was held in the U.S. soil since American Ninja Warrior 4), as it eliminated Najee Richardson. Since he timed out on the obstacle, this also became the first ever Stage Two's time-out on American Ninja Warrior.