Corrosion in marine buildings both onshore and offshore can cause many losses. One of the main causes of biocorrosion is biofouling. Biofouling itself is an accumulation of undesirable biological matter on the surface of material and is caused either by macroorganism such as bacteria, fungi, microalgae, and protozoa. Escherichia coli could affect the rate of metal corrosion due to this bacteria can produce polymer during biofilm formation. The Impressed Current Anti Fouling (ICAF) method is one way to prevent the biofouling. The aim of research was to determine reduction of Escherichia coli population using simple ICAF system. The simple ICAF reactor was operated with variation of electric current (0.1, 0.3 and 0.5 A) and duration time (5, 7 and 10 min). Steel of AH36 has role as an activated cathode, meanwhile pure copper (Cu) was as an anode. Simple ICAF system was arranged with plastic containers that filled with Escherichia coli. The population of Escherichia coli was determined using Colony Forming Unit (CFU) method. The concentration of ion Cu was analyzed using Atomic Absorption Spectrophotometer. The other parameter that was observated was the pH, salinity and temperature during operation of simple ICAFsystem. Based on results, the time duration was longer and variation of electrical current was higher at ICAF system operation so that the reduction of Escherichia coli increased. The population Escherichia coli reduction reached over 90% for 10 min at all variation of electrical current. The range of Cu concentrations were 1.2 mg/L - 28.8 mg/L. In conclusion, ion Cu that was produced during operation of simple ICAF system can reduce Escherichia coli population.