Basics: Water Release is one of the five basic chakra natures, and is normally used to attack with concussive force by manipulating the water in your surroundings, or by creating it yourself. It's also one of the most versatile elements because of it's natural ability to change shape due the things it comes in contact with. Water release is also affiliated with certain clans, such as the Hokuki.
KKGs that list Water as a mandatory component: Ice Release, Wood Release, Storm Release, and Boil Release.
Strengths/Weaknesses:
Fire: Water, due to it's cool nature, can smother and cool down flames, making it quite strong against the Fire element. Though, if a very powerful fire attack meets a weak water attack, Evaporation may occur.
Earth: Due to water's natural ability to change shape that I mentioned earlier, Earth naturally is strong against water because of Earth's status as solid matter.
Lightning: Lightning, being naturally attracted to water can be used to power-up water attacks and increase their range.
Wind: Wind, while not having much of an offensive advantage against water, can be used to cut/slash or weaken the concussive force of water attacks, and if an attack is based around it's unique shape, it could nullify it completely.
*After answering his Sensei's question, Richter takes Hiruzen's pipe and replaces it with one that blows bubbles.*
Richter: It's only fitting