The development of corrosion in sewers is largely aggravated due to frequent occurrences of wastewater inoculation. This study comprehensively evaluated the impacts of different types of wastewater inoculation on the corrosion development through a 300-day experiment using concrete at different corrosion stages. It was found that wastewater inoculation increased the corrosion losses, especially for the initial stages of corrosion development. However, the effects could not be captured by measuring surface pH and sulfide uptake rate. The wastewater can bring complicated effects of acid neutralization, wash-off of corrosion layer and biofilms scouring in addition to the commonly accepted microbial inoculation.