Remove the locking lid from your 35- or 55-gallon plastic drum.
Fill the drum with water until it reaches the top.
Secure the lid onto the drum. Food grade drums seal watertight, so you can place the drum on its side without fear of the water leaking out.
Carefully place the drum on its side. It will likely take two or more people to place the drum on its side. Do not simply push the drum over. This could cause the lid to fail and water to spill everywhere.
Roll the drum over your lawn to compact it.
Stand the drum up and remove the lid from the drum when finished. Do not waste the water. Recycle it and use to water plants, gardens or other landscaping that require water.