Stormwater FAQ

What is Stormwater?

Stormwater is the flow of water that occurs immediately after rainfall or as a result of snow melt. When it rains, several things can happen to the precipitation. Some of the rain water is absorbed into the ground and some evaporates. The rest of the rain water that runs off land surfaces and impervious areas is Stormwater.

Hard surfaces – such as pavement and rooftops – are called 'impervious surfaces' and do not allow rainfall to absorb into the ground. When there is more hard or impervious surface in a community, there will be more stormwater runoff.

To keep stormwater from flooding roads and property, storm drain systems divert and carry and stormwater directly to streams, rivers and lakes.

Can stormwater cause problems?

Yes. Stormwater picks up pollutants such as oil and grease, chemicals, nutrients, metals, and bacteria as it travels across land and carries it directly into our rivers and lakes. Unlike the water in sewer systems, stormwater is not treated before being released into rivers or lakes.