Water decomposition, also known as electrolysis, is a process where water molecules are broken down into hydrogen and oxygen gas using an electric current. It's important to distinguish between temperature and electrolysis because they are not the same thing.

Temperature alone does not decompose water.

Here's why:

* Thermal Decomposition: Some substances decompose when heated to a high enough temperature. However, water is relatively stable and requires a significant amount of energy to break the bonds between hydrogen and oxygen atoms.

* Electrolysis: This process involves applying an electrical current to water, providing the energy needed to break the chemical bonds. It doesn't necessarily require high temperatures.

Therefore, there is no specific temperature at which water decomposes. Water decomposition occurs due to the application of electricity during electrolysis, not just through heating.