14. Do landfills cause water pollution?

Water pollution from landfills is a significant concern.

Landfills threaten water supplies when water percolates through waste, picking up toxic materials such as metals, minerals, organic chemicals, bacteria and viruses (EPA). This polluted liquid is commonly called “leachate”.

There is no way of preventing rainwater or snow melt from entering a landfill. This is why most jurisdictions now require landfills to have impermeable layer at the bottom to prevent the pollution from entering groundwater supplies (the bottom liner system).

Landfill leachate must be monitored and treated similarly to municipal sewage.