Monosodium methylphosphonate is primarily used as a corrosion inhibitor in water treatment systems, particularly in cooling towers and boilers. It helps prevent scale formation and protects metal surfaces from corrosion, extending the lifespan of equipment. Additionally, it is employed in the formulation of detergents and cleaning agents, where it acts as a chelating agent to bind metal ions and improve cleaning efficiency. In agriculture, it is utilized as a component in fertilizers to enhance phosphorus availability for plants. Its stability and effectiveness in various pH conditions make it a versatile chemical in industrial and agricultural applications.