It's not only illegal in many places, but it's also bad for the environment to dump chemicals down the storm drain in front of your house. It is the job of storm drains to quickly transport runoff from rain and snowmelt from streets and buildings to neighboring waterways. Stormwater normally does not undergo any sort of treatment before it is discharged into waterways such as streams, rivers, lakes, or seas, in contrast to wastewater that is sent to treatment plants.
Dumping undesirable chemicals down a storm drain is the same as releasing them directly into the environment, where they can harm wildlife, vegetation, and even humans. Long-term exposure to these substances can also have disastrous effects on ecosystems.
It is also against the law in many places to dump chemicals down a storm drain. Many communities have ordinances in place that make it illegal to dump hazardous garbage in the wrong places, with fines and other punishments for those who do.
Instead of dumping undesirable chemicals down a storm drain, reach out to your local county or city government to find out when there next hazardous waste collection event will be. If they don't yet have a program contact your states environmental protection division to inquire about their events.
Help play a part in keeping your environment free from pollution.