A new test method for evaluating the resistance of cementitious products and materials to biogenic acid attack,labelled BAC-Test for Biogenic Acid attack on Concrete Test, has been developed.It consists of inoculating pipes with a highly diverse microbial consortium (from an urban wastewater treatment plant), and trickling a feeding solution containing a safe and soluble reduced sulfur source over the inoculated surface in order to select a sulfur-oxidizing activity.A sulfur substrate, thiosulfate, was used in the feeding solution, which facilitated the monitoring of the bacterial activity, and of the leaching of cementitious ions.The functioning of the test in terms of selection of sulfur oxidizing microorganisms, acid and sulfate production, and degradation mechanisms occurring in the cementitious materials has been validated previously.