The present study was performed to evaluate the effect of irrigation wastewater on contamination and quality of forage and corn silage in herds were fed with corn silage. The estimation of chemical compounds between wastewater treatment and well water were performed. In corn silage which irrigated with wastewater in compared to well water had a lower crude protein, pH, and acetic acid percentage (P 0.01) and had a higher non-fibrous carbohydrates percentage, propionic acid (P 0.05) and butyric acid (P = 0.08). Propionic acid and butyric acid were not detected in well water treatment. The existence of pathogens of E.coli and salmonella were evaluated between wastewater, well water treatments in corn forage, corn silage and milk of dairy herds were fed by this type of silage. The E.coli colony and salmonella population was observed (P 0.05). In corn plant which irrigated with wastewater, E.coli colony (P 0.05) was observed. The corn silage was irrigated with wastewater, E.coli colony and in corn silage irrigated with semi-wastewater and well water colony and salmonella were numerically higher. In milk tanks of herds were fed with corn silage which irrigated with wastewater, E.coli colony and salmonella were numerically higher. Heavy metal, lead and cadmium between wastewater and well water treatments were investigated in corn silage, milk and water of herds. The density of lead was measured in wastewater was higher in compared to well water (P 0.01). The density of lead in the milk of herds were fed with corn silage which irrigated with wastewater was numerically higher in density of lead in the milk of herds were fed with corn silage with well water. The density of lead in corn silage was irrigated with well water in numerically was higher than corn silage was irrigated with wastewater. Ammonium nitrogen was higher in wastewater (P 0.01). The electrical conductivity was higher in well water than wastewater (P 0.01) and pH was not significant. The density of aflatoxin and zearalenone in corn silage was irrigated with wastewater were up to allowed limit. The results of this study confirm the existence of various pollutants such as pathogens of E.coli and salmonell, heavy and toxic elements had a negative impact on the quality and quantity of corn silage that was irrigated with wastewater. Keywords: Silage corn, Wastewater, Well water, Heavy elements, Pathogenic factors.