Concrete in land-fill areas, in former swamps and marshes, in areas near the ocean and even concrete sprayed by sprinklers used to water shrubbery can be saturated with water that contains salts harmful to it. Some of these salts merely cause efflorescence. Others attack concrete chemically. Salts that can create one problem or another include some of the chlorides, sulfates, carbonates, phosphates, nitrates and sulfides of such ions as: sodium, potassium, magnesium, calcium, aluminum, iron and zinc. Less frequently, mixing water may contain substances that may reduce the strength or change the setting time of concrete. The portable test kit featured in the article can be used to determine whether various salts are in a water sample without sending samples to a laboratory. It can also be used to check for corrosion of reinforcing steel in concrete.