Every catch basin in the country—this includes all the drains you see along the road and in parking lots—should be cleaned at least once a year. Most cities enforce this on an annual inspection basis, and property managers face the threat of fines if it’s not done in time. But why? Simple. The sediment that collects in the catch basins build up and gets swept away during storms. And that sediment carries with it a whole host of chemicals and bacteria—not to mention the sediment itself—that end up in our lakes, rivers, and oceans.