Question: I need to prevent spills from getting into storm drains near my loading dock so that I don’t violate my stormwater permit. Do inexpensive magnetic drain covers really work?
Answer: Many storm drains are comprised of a metal grate that sets in a concrete frame. For a drain cover to be effective, it has to create a seal over the entire drain.
Magnetic drain covers are traditionally lightweight sheets of magnet that cling to the metal grate. The problem is that they have no way to attach themselves to the concrete frame of the drain. Because of this, liquids — which seek the path of least resistance — can channel their way around the metallic parts of the grate and escape. In some spill scenarios, the force of liquid entering the drain can also dislodge the magnetic cover, making it completely ineffective.
By contrast, polyurethane drain covers don’t rely on magnetism to create a seal. They will stick to any flat surface (concrete, metal, plastic, etc.) to create a complete seal over the entire drain, not just the metal grate. These covers will stop a spill in its tracks and help to prevent a reportable release and lengthier cleanup.