Does Methyl Iodide (CH3I) react with water (H2O) and if it does what would be its byproducts?
Methyl iodide is hydrolyzed by water in an $\ce{S_{N}2}$ reaction ($\ce{S_{N}1}$ is disfavored by the instability of the primary methyl cation), which yields methanol and hydroiodic acid as products.

$$\ce{CH3I + H2O &lt;=&gt; CH3OH2^+ + I-}$$
$$\ce{CH3OH2^+ + H2O &lt;=&gt; H3O+ + CH3OH}$$

A possible side reaction is the formation of iodine and methane by the redox reaction

$$\ce{CH3I + H3O+ + I- &lt;=&gt; CH4 + I2 + H2O}$$

However, this reaction becomes only important when a large concentration of methanol pushes the hydrolysis equilibrium to the educt side. It is negligible in pure aqueous solution (reference).