Nano zero-valent iron (nZVI) is one of the most prominent examples of a rapidly emerging technology for the treatment of contaminated soil and groundwater. These particles were used successfully to absorb various heavy metals (e.g., Pb²⁺, Ba²⁺, As⁵⁺, As³⁺, Cr⁶⁺, Co²⁺, Cd²⁺, Cu²⁺), chlorinated organic contaminants (e.g., solvents, pesticides), nitrate and so on. nZVI particles have a large surface area and high surface reactivity. However, the agglomeration, oxidation by non-target compounds and high mobility in the aqueous solutions are the major challenges of nZVI use in environmental remediation. In general, there are several gaps concerning fate, transport and toxicity of nZVI. In recent years, considerable efforts have been made to overcome these problems. These efforts include synthetic methods, surface property modification, trapping of nZVI in different beads and enhancement for field delivery and reactions. This paper provides an overview of research on reclamation of unconventional water with nZVI.