Remove any large debris from the storm drain. Use a shovel, if necessary.
Sweep away leaves and twigs with a broom. Or use a rake.
Remove any smaller items stuck in the grate, but wear gloves while doing so. Once the leaves and other debris have been removed, the water flow should be restored to the drain and the storm drain should no longer overflow.
Pour a cup of baking soda down the storm drain. Pour a cup of vinegar down the drain, following the baking soda. The solution will mix together and work through any clogs in the drain. After 15 to 20 minutes, pour a pot of boiling water down the storm drain to flush the solution through. Do not use commercial clog-removing solutions on the storm drains, as they often drain to lakes, creaks and other bodies of water. The chemicals contained in these products can be hazardous to these environments.