Definitions & Terms

Best Management Practices (BMPs)

Good housekeeping solutions that include the proper handling, storage, and disposal of toxic materials to prevent stormwater pollution.

Catch Basins

Curbside opening that collects rainwater from streets and serves as an entry point to the storm drain system.

First Flush

The first big rain after an extended dry period, which flushes out the accumulated pollutants in the storm drain system.

Flood Control Channel

The open portion (often concrete-lined) of the storm drain system.


The edge of a street (below the curb) designed to drain water runoff from streets, driveways and parking lots into catch basins.

Household Hazardous Waste

Common everyday products that people use in and around their homes including paint, paint thinner, herbicides, and pesticides that, due to their chemical nature, can be hazardous if not properly disposed.

Illegal Discharge

Any disposal into the storm drain system for which a person or business does not have a permit.

Illicit Connection

Any connection to the storm drain system that is not permitted: or any legitimate connection that is used for illegal discharge.

Non-Point Source Pollution

Pollution that does not come from a single, identifiable source. Includes materials that wash from roofs, streets, yards, driveways, sidewalks and other land areas. Collectively, this is the largest source of stormwater pollution.


A flow of water from one drainage system into a larger system, or into a body of water like a wash bay, or lake.

Point Source Pollution

Pollution from a single identifiable source such as a factory or a sewage-treatment plant. Most of this pollution is highly regulated at the state and local levels.

Source Control

Action to prevent pollution where it originates.

Storm Drain System

A vast network of underground pipes and open channels designed for flood control.


Rainwater that enters the storm drain system and empties into lakes, rivers, streams.

Storm Water Pollution

Water from rain, irrigation, garden hoses or other activities that picks up pollutants (cigarette butts, trash, automotive fluids, used oil, paint, fertilizers and pesticides, lawn and garden clippings and pet waste) from streets, parking lots, driveways and yards and carries them through the storm drain system.


A watershed is land that collects water and drains it into a river system or lake. Salt Lake County's watershed includes the Wasatch Range, Salt Lake Valley, and a network of waterways. The mountains capture rain and snow which give birth to the streams and rivers that water the arid valley. These waterways drain into the Jordan River, which in turn empties into the Great Salt Lake.