AbstractThe action of dilute aqueous solutions of representative anionic, cationic and non‐ionic wetting agents on mild‐steel sheet has been studied. Three types of water have been used: London tap‐water, distilled water, and tap‐water softened by the zeolite base‐exchange process. The effects of varying the pH of the water used from 2 to 12, and of temperature changes, have been investigated.Most of the anion‐active agents used caused adsorption of organic anions, either on the metal itself, or on the initial corrosion products, so modifying the normal action of plain waters. The cation‐active agents did not produce adsorbed films, but the alkalinity of triethanolamine solutions reduced the extent of rusting.Changes in the pH of the water used to prepare solutions produced little effect, although increased pH caused greater activity in solutions of cationic agents containing bromine.In general, rise of temperature caused increased attack, although the reduced solubility of oxygen mitigated this effect.Results have been expressed graphically and a mechanism is suggested.