An illicit discharge is any pollutant discharged to a storm sewer system that is harmful to the health or welfare of people, the environment, wildlife or surface waters. Illicit discharges include:

• Sediment washing from construction sites
• Chemical or oil spills
• Sewage from broken sewer lines or overflow from private septic systems
• Pesticides, herbicides, or wash water from paint clean up and concrete washout

Illicit discharges could be intermittent - only occurring a few minutes per day or a few days per year, continuous - occurring almost daily, or transitory - only occurring once.

Which activities are not considered illicit discharges?

Water line flushing, residential car washing or draining swimming pools that are dechlorinated (left to rest for seen or more days after treatment), firefighting and lawn watering are not considered illicit.

It only takes a very small amount of many types of chemicals to harm fish, plants and other aquatic organisms. For example, just one teaspoon of mercury is enough to contaminate more than 13 Olympic-sized swimming pools of drinking water. Another example is discharging concrete washout into a lake or stream; this action can kill fish due to increases in pH.

Most of these chemicals enter our water systems through improper or accidental disposal outside.