You can't "neutralize" water in the sense of making it disappear or rendering it harmless. Water (H₂O) is a fundamental molecule and a vital component of life.

However, if you're referring to neutralizing the acidity or alkalinity of water, here are some substances you could use:

* For acidic water (low pH): A base like calcium hydroxide (Ca(OH)₂), also known as slaked lime, or sodium bicarbonate (NaHCO₃), commonly called baking soda.

* For alkaline water (high pH): An acid like hydrochloric acid (HCl).

It's important to note that neutralizing water's pH requires careful calculations and should only be done by someone with a strong understanding of chemistry. Incorrectly neutralizing water could result in harmful consequences.