Rid O' rust extreme water concentrate is the superior, cost-effective rust preventer for use with irrigation systems with low or fluctuating pH water. It neutralizes iron in well water to prevent ugly rust stains on your property, extends the life of your sprinkler components and prevents costly maintenance calls. Rid O' Rust is safe for people, pets and plants when used as directed. In order to determine the proper chemical to use, the well water must be tested for iron content, hardness and pH.