It was studied the suppression process of corrosion of steel in Chisinau tap water, which by total content of chloride and sulfate ions (more than 150 mg/l) is a strong corrosive medium and by value of Langelie index (-0.08) is close to its equilibrium state. As inhibitor has been used a representative of a number of saturated dibasic acid - adipic acid: formula  with concentration of 0,025-0,75 g/l.This acid is important in the preparation of polymer compounds. It is formed by the oxidation of fats. It is used in small quantities in the food industry to replace the citric and tartaric acids. This acid is also found in beet juice. It is shown that the greatest effect is achieved by inhibiting the corrosion of steel when is used in an amount of 0,025-0,75 g/l of adipic acid. Thus, when the inhibitor concentration is 0,05 g/l and at 8 and 24 hours of testing, the corrosion losses are reduced accordingly 7,8 and 6 times, providing a degree of protection Z equal to 87,2% and 85% respectively. At inhibitor concentration of 0,1 g/l at 24 hours of test, the corrosion rate is reduced by 5.5 times, and at a concentration of 0,25 g/l and 72 hours of tests, the braking coefficient is 5.5. The quantity of inhibitor introduced into the corrosive medium, play a crucial role. The lower limit of the concentration is equal to 0,025 g/l, because at lower levels of the administration of the inhibitor in the medium insignificantly reduces the corrosion losses. The upper limit of concentration of inhibitor is to be regarded as 0,75 g/l, as a further increase in the concentration the corrosive loss only slightly decrease, but is growing the costs of inhibitor.