The present work was carried out with the purpose of validating an analytical method for the determination of residual aluminum in drinking water by means of visible spectrophotometry according to the Eriochrome Cyanine R 3500B-(Al) method of Standard Methods Ed. 2012. The analyzes were performed at a wavelength of 535 nm. The determination of residual aluminum according to the method was carried out in a Spectrophotometric Equipment of UV/Visible Sweep SQ-2800 of Single Haze brand UNICO. The tests were carried out in the Laboratory of Water Quality of the company Proactiva Aguas de Monteria S.A. E.S.P. of the city of Monteria.The validation parameters obtained experimentally showed results that are within those established for a validation, for the determination of residual aluminum by the spectrophotometric method Eriocromo Cianina R, the working range was evaluated from 0.03 to 0.3 mg Al3+/L, the detection limit of the method was 0.017 mg Al3+/L, the accuracy of the method was reported as a percentage of recovery, obtaining values of 97.8 % for low range, 93.6 % for midrange and 90.9 % for High range and error rate giving results of 4.81 % for low range, 2.29 % for midrange and 1.07% for high range. Finally, we obtained uncertainty values of 1.36% for the low range, 1.48 % for the midrange and 1.53 % for the high range.It was demonstrated that the validated chemical method complies with the requirements of the water quality control laboratory of the company Proactiva Aguas de Monteria and is therefore suitable for its application in the quality control of drinking water, according to the conditions requirements and requirements established by standard NTC/ISO/IEC 17025:2005.